\batchmode \documentstyle[makeidx,epsf,psfig,fleqn,comment]{book} \makeatletter \pagenumbering{roman} \setcounter{tocdepth}{2} \makeindex \addtolength{\textwidth}{4pc} \addtolength{\textheight}{6pc} \emergencystretch=25pt \renewcommand{\floatpagefraction}{.75} \renewcommand{\topfraction}{.85} \advance\textfloatsep-8pt \def\inv{^{-1}} \newcommand{\ii}[1]{{\it #1}} \newcommand{\tty}[1]{{\tt #1}} \long\def\glossaryentry#1#2{\glossitem#1<<}\long\def\glossitem#1:#2<<{\item[#1]\ignorespaces #2} \hyphenation{Eijk-hout} \def\glossaryentry#1#2{\glossitem#1<<} \def\glossitem#1:#2<<{\item[#1]\ignorespaces #2} \def\half{{\frac{1}{2}}} \def\cgs{{CGS}} \def\cg{{ CG}} \def\bicg{{BiCG}} \def\cgstab{{ Bi-CGSTAB}} \def\qmstab{QMRCGSTAB} \def\qmrcgstab{QMRCGSTAB} \def\tfqmr{TFQMR} \def\qmrcgs{QMRCGS} \def\qmr{QMR} \def\bcg{{BiCG}} \def\ncofm{M_1\inv AM_2\inv} \def\omip{\Omega'_i} \def\omi{\Omega_i} \makeatother \newenvironment{tex2html_wrap}{}{} \begin{document} \pagestyle{empty} \setcounter{tocdepth}{2} \newcounter{utk-thanks} \newcounter{ornl-thanks} \newcounter{ucla-thanks} \setcounter{utk-thanks}{\value{footnote}} \setcounter{ucla-thanks}{\value{footnote}} \setcounter{ornl-thanks}{\value{footnote}} \newpage {\samepage \clearpage $^,$ } \newpage {\samepage \clearpage \begin{tabular}% latex2html id marker 64 {l l} $A, \ldots, Z$ & matrices \\ $a, \ldots, z$ & vectors \\ $\alpha, \beta, \ldots, \omega$ & scalars \\ $A^{T}$ & matrix transpose \\ $A^{H}$ & conjugate transpose (Hermitian) of $A$ \\ $A^{-1}$ & matrix inverse \\ $A^{-T}$ & the inverse of $A^T$ \\ $a_{i,j}$ & matrix element \\ $a_{.,j}$ & $j$th matrix column \\ $A_{i,j}$ & matrix subblock \\ $a_{i}$ & vector element \\ $u_x,u_{xx}$ & first, second derivative with respect to~$x$ \\ $(x,y)$, $x^Ty$ & vector dot product (inner product) \\ $x^{(i)}_j$ & $j$th component of vector $x$ in the $i$th iteration\\ diag($A$) & diagonal of matrix $A$ \\ diag($\alpha, \beta \ldots$) & diagonal matrix constructed from scalars $\alpha, \beta \ldots$\\ span($a,b \ldots$) & spanning space of vectors $a,b \ldots$ \\ $\cal R$ & set of real numbers \\ ${\cal R}^{n}$ & real $n$-space\\ $|| x ||_{2}$ & 2-norm \\ $|| x ||_{p}$ & $p$-norm \\ $|| x ||_{A}$ & the ``$A$-norm'', defined as $(Ax,x)^{1/2}$ \\ $\lambda_{\max}(A), \lambda_{\min}(A)$ & eigenvalues of $A$ with maximum (resp. minimum) modulus \\ $\sigma_{\max}(A), \sigma_{\min}(A)$ & largest and smallest singular values of $A$ \\ $\kappa_2 (A)$ & spectral condition number of matrix $A$ \\ $\cal L$ & linear operator \\ $\overline{\alpha} $ & complex conjugate of the scalar $\alpha$ \\ $\max \{S\}$ & maximum value in set $S$ \\ $\min \{S\}$ & minimum value in set $S$ \\ $\sum $ & summation \\ $O(\cdot)$ & ``big-oh'' asymptotic bound \\ & \\ \end{tabular} } \newpage {\samepage \clearpage \begin{tabular}{l l} \multicolumn{2}{c}{Conventions Used in this Book}\\ & \\ $D$ & diagonal matrix \\ $L$ & lower triangular matrix \\ $U$ & upper triangular matrix \\ $Q$ & orthogonal matrix \\ $M$ & preconditioner \\ $I,\; I^{n \times n}$ & $n \times n$ identity matrix \\ $\hat{x}$ & typically, the exact solution to $Ax=b$\\ $h$ & discretization mesh width \\ \end{tabular} } \stepcounter{chapter} \newpage {\samepage \clearpage $A$ } \newpage {\samepage \clearpage $y=A \cdot x$ } \newpage {\samepage \clearpage $z=A^T \cdot x$ } \newpage {\samepage \clearpage $y$ } \newpage {\samepage \clearpage $z$ } \newpage {\samepage \clearpage $x$ } \stepcounter{section} \stepcounter{section} \stepcounter{chapter} \stepcounter{section} \newpage {\samepage \clearpage $\omega$ } \newpage {\samepage \clearpage $Ax=b$ } \newpage {\samepage \clearpage $(A A^T) y = b$ } \newpage {\samepage \clearpage $x=A^T y$ } \newpage {\samepage \clearpage $(A^TA) x = \tilde{b}$ } \newpage {\samepage \clearpage $\tilde{b} = A^T b$ } \newpage {\samepage \clearpage $A A^T$ } \newpage {\samepage \clearpage $A^TA$ } \newpage {\samepage \clearpage $A^T$ } \stepcounter{section} \newpage {\samepage \clearpage \begin{equation} x^{(k)} = B x^{(k-1)} + c \label{eqn:stationary} \end{equation} } \newpage {\samepage \clearpage $B$ } \newpage {\samepage \clearpage $c$ } \newpage {\samepage \clearpage $k$ } \stepcounter{subsection} \newpage {\samepage \clearpage $n$ } \newpage {\samepage \clearpage $i$ } \newpage {\samepage \clearpage \begin{displaymath} \sum_{j=1}^n a_{i,j} x_j = b_i, \end{displaymath} } \newpage {\samepage \clearpage $x_i$ } \newpage {\samepage \clearpage \begin{equation}% latex2html id marker 226 x_i = (b_i - \sum_{j \neq i} a_{i,j} x_j) / a_{i,i}. \label{eqn:ith-equation} \end{equation} } \newpage {\samepage \clearpage \begin{equation} x^{(k)}_i = (b_i - \sum_{j \neq i} a_{i,j} x^{(k-1)}_j) / a_{i,i}, \label{eqn:jacobi-pointwise} \end{equation} } \newpage {\samepage \clearpage \begin{equation} x^{(k)} = D^{-1} (L+U) x^{(k-1)} + D^{-1} b, \label{eqn:jacobi-matrixwise} \end{equation} } \newpage {\samepage \clearpage $D$ } \newpage {\samepage \clearpage $-L$ } \newpage {\samepage \clearpage $-U$ } \newpage {\samepage \clearpage $\bar{x}$ } \newpage {\samepage \clearpage $x^{(k-1)}$ } \newpage {\samepage \clearpage $x^{(k)}$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.0in] {\vbox{ \begin{tabbing} Choose an initial guess $x^{(0)}$ to the solution $x$. \\ {\bf for } \= $ k = 1, 2, \ldots$ \\ \> {\bf for } \= $ i = 1, 2, \ldots , n$ \\ \> \> $\bar{x}_i = 0 $ \\ \> \> {\bf for } \= $ j = 1, 2, \ldots, i-1, i+1, \ldots, n$ \\ \> \> \> $\bar{x}_i = \bar{x}_i + a_{i,j} x^{(k-1)}_j $ \\ \> \> {\bf end} \\ \> \> $\bar{x}_i = (b_i - \bar{x}_i) / a_{i,i} $ \\ \> {\bf end} \\ \> $ x^{(k)} = \bar{x} $ \\ \> check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:jacobi} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{displaymath} {\cal L}u=-u_{xx}=f\qquad\hbox{on $(0,1)$}, \qquad u(0)=u_0,\quad u(1)=u_1, \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} Lu(x_i)=2u(x_i)-u(x_{i-1})-u(x_{i+1})=f(x_i)/N^2\qquad \hbox{for $x_i=i/N$, $i=1\ldots N-1$}. \end{displaymath} } \newpage {\samepage \clearpage $\cal L$ } \newpage {\samepage \clearpage $L$ } \newpage {\samepage \clearpage $n=1\ldots N-1$ } \newpage {\samepage \clearpage $u_n(x)=\sin n\pi x$ } \newpage {\samepage \clearpage $\lambda=4\sin^2n\pi/(2N)$ } \newpage {\samepage \clearpage $\lambda(B)=1-\lambda(L)/2=1-2\sin^2n\pi/(2N)$ } \newpage {\samepage \clearpage $u_n$ } \newpage {\samepage \clearpage $1$ } \newpage {\samepage \clearpage $\approx 1-10/N^2$ } \newpage {\samepage \clearpage $u(x)=\sin\pi x$ } \newpage {\samepage \clearpage $\max\{|\lambda(A)|\}$ } \newpage {\samepage \clearpage $1-O(h^2)$ } \newpage {\samepage \clearpage $h$ } \newpage {\samepage \clearpage $h=N^{-d}$ } \newpage {\samepage \clearpage $N$ } \newpage {\samepage \clearpage $d$ } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{equation} x^{(k)}_i = (b_i - \sum_{ji} a_{i,j} x^{(k-1)}_j) / a_{i,i}. \label{eqn:gauss-seidel-pointwise} \end{equation} } \newpage {\samepage \clearpage \begin{equation} x^{(k)} = (D-L)^{-1} (Ux^{(k-1)} + b). \label{eqn:gauss-seidel-matrixwise} \end{equation} } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.0in] {\vbox{ \begin{tabbing} Choose an initial guess $x^{(0)}$ to the solution $x$. \\ {\bf for } \= $ k = 1, 2, \ldots$ \\ \> {\bf for } \= $ i = 1, 2, \ldots , n$ \\ \> \> $ \sigma = 0 $ \\ \> \> {\bf for } \= $j = 1, 2, \ldots, i-1$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k)}_j $ \\ \> \> {\bf end} \\ \> \> {\bf for } $j = i+1, \ldots, n$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k-1)}_j $ \\ \> \> {\bf end} \\ \> \> $ x^{(k)}_i = (b_i - \sigma) / a_{i,i} $ \\ \> {\bf end} \\ \> check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:gs} \end{center} \end{figure} } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{displaymath} x_i^{(k)} = \omega \bar{x}_i^{(k)} + (1 - \omega )x_i^{(k-1)} \end{displaymath} } \newpage {\samepage \clearpage \begin{equation} x^{(k)} = (D - \omega L)^{-1} (\omega U + (1-\omega)D) x^{(k-1)} + \omega (D - \omega L)^{-1} b . \label{eqn:sor-matrix} \end{equation} } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.0in] {\vbox{ \begin{tabbing} Choose an initial guess $x^{(0)}$ to the solution $x$. \\ {\bf for } \= $ k = 1, 2, \ldots$ \\ \> {\bf for } \= $ i = 1, 2, \ldots , n$ \\ \> \> $ \sigma = 0 $ \\ \> \> {\bf for } \= $j = 1, 2, \ldots, i-1$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k)}_j $ \\ \> \> {\bf end} \\ \> \> {\bf for } $j = i+1, \ldots, n$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k-1)}_j $ \\ \> \> {\bf end} \\ \> \> $ \sigma = (b_i - \sigma) / a_{i,i} $ \\ \> \> $ x^{(k)}_i = x^{(k-1)}_i + \omega (\sigma - x^{(k-1)}_i) $ \\ \> {\bf end} \\ \> check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:sor} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $\omega = 1$ } \newpage {\samepage \clearpage $(0,2)$ } \newpage {\samepage \clearpage $0 < \omega < 1$ } \newpage {\samepage \clearpage $\omega \in (0,2)$ } \newpage {\samepage \clearpage $\omega = 2 - O(h)$ } \newpage {\samepage \clearpage $M$ } \newpage {\samepage \clearpage $a_{i,j}=a_{j,i}$ } \newpage {\samepage \clearpage $j$ } \newpage {\samepage \clearpage $x^TAx>0$ } \newpage {\samepage \clearpage $a_{ii}>\sum_{j\not=i}|a_{ij}|$ } \newpage {\samepage \clearpage $a_{i,j}\leq0$ } \newpage {\samepage \clearpage $i\not=j$ } \newpage {\samepage \clearpage $(A^{-1})_{i,j}\geq0$ } \newpage {\samepage \clearpage $\rho$ } \newpage {\samepage \clearpage \begin{equation} \omega_{\rm opt} = \frac{2}{1 + \sqrt{1 - \rho^2}}. \label{eqn:sta:optimal:omega} \end{equation} } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{equation} x^{(k)} = B_1 B_2 x^{(k-1)} + \omega (2-\omega)(D-\omega U)^{-1} D (D- \omega L)^{-1} b, \label{eqn:ssor-matrix} \end{equation} } \newpage {\samepage \clearpage \begin{displaymath} B_1 = (D- \omega U)^{-1} (\omega L + (1-\omega) D), \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} B_2 = (D- \omega L)^{-1} (\omega U + (1-\omega) D). \end{displaymath} } \newpage {\samepage \clearpage $B_2$ } \newpage {\samepage \clearpage $B_1$ } \newpage {\samepage \clearpage $U$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.0in] {\vbox{ \begin{tabbing} Choose an initial guess $x^{(0)}$ to the solution $x$. \\ Let $x^{({\frac{1}{2}})}=x^{(0)}$.\\ {\bf for } \= $ k = 1, 2, \ldots$ \\ \> {\bf for } \= $ i = 1, 2, \ldots , n$ \\ \> \> $ \sigma = 0 $ \\ \> \> {\bf for } \= $j = 1, 2, \ldots, i-1$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k-{\frac{1}{2}})}_j $ \\ \> \> {\bf end} \\ \> \> {\bf for } $j = i+1, \ldots, n$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k-1)}_j $ \\ \> \> {\bf end} \\ \> \> $ \sigma = (b_i - \sigma) / a_{i,i} $ \\ \> \> $ x^{(k-{\frac{1}{2}})}_i = x^{(k-1)}_i + \omega (\sigma - x^{(k-1)}_i) $ \\ \> {\bf end} \\ \> {\bf for } $ i = n, n-1, \ldots , 1$ \\ \> \> $ \sigma = 0 $ \\ \> \> {\bf for} $j = 1, 2, \ldots, i-1$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k-{\frac{1}{2}})}_j $ \\ \> \> {\bf end} \\ \> \> {\bf for} $j = i+1, \ldots, n$ \\ \> \> \> $ \sigma = \sigma + a_{i,j} x^{(k)}_j $ \\ \> \> {\bf end} \\ \> \> $ x^{(k)}_i = x^{(k-{\frac{1}{2}})}_i + \omega (\sigma - x^{(k-{\frac{1}{2}})}_i) $ \\ \> {\bf end} \\ \> check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:ssor} \end{center} \end{figure} } \stepcounter{subsection} \stepcounter{section} \stepcounter{subsection} \newpage {\samepage \clearpage $x^{(i)}$ } \newpage {\samepage \clearpage % latex2html id marker 5039 $(\alpha_i)$ } \newpage {\samepage \clearpage $p^{(i)}$ } \newpage {\samepage \clearpage \begin{displaymath}% latex2html id marker 515 x^{(i)} = x^{(i-1)}+\alpha_i p^{(i)}. \end{displaymath} } \newpage {\samepage \clearpage $r^{(i)}=b-Ax^{(i)}$ } \newpage {\samepage \clearpage \begin{equation}% latex2html id marker 523 r^{(i)} = r^{(i-1)}-\alpha q^{(i)}\qquad\hbox{where}\qquad q^{(i)}=Ap^{(i)}. \label{eqn:cg:res-update} \end{equation} } \newpage {\samepage \clearpage % latex2html id marker 5045 $\alpha = \alpha_i=r^{(i-1)^T}r^{(i-1)}/p^{(i)^T}Ap^{(i)}$ } \newpage {\samepage \clearpage $r^{(i)^T}A^{-1}r^{(i)}$ } \newpage {\samepage \clearpage % latex2html id marker 5049 $\alpha$ } \newpage {\samepage \clearpage \begin{equation} p^{(i)} = r^{(i)}+\beta_{i-1}p^{(i-1)}, \label{eqn:cg:dir-update} \end{equation} } \newpage {\samepage \clearpage $\beta_i=r^{(i)^T}r^{(i)}/r^{(i-1)^T}r^{(i-1)}$ } \newpage {\samepage \clearpage $Ap^{(i-1)}$ } \newpage {\samepage \clearpage $r^{(i)}$ } \newpage {\samepage \clearpage $r^{(i-1)}$ } \newpage {\samepage \clearpage $\beta_i$ } \newpage {\samepage \clearpage $Ap^{(j)}$ } \newpage {\samepage \clearpage $r^{(j)}$ } \newpage {\samepage \clearpage $M=I$ } \newpage {\samepage \clearpage $z^{(i-1)}$ } \newpage {\samepage \clearpage $z^{(0)}$ } \newpage {\samepage \clearpage $r^{(0)}$ } \newpage {\samepage \clearpage \begin{figure}% latex2html id marker 567 [tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Compute $r^{(0)} = b - Ax^{(0)}$ for some initial guess $x^{(0)}$ \\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \> {\bf solve} $Mz^{(i-1)}=r^{(i-1)}$\\ \> $\rho_{i-1}=r^{(i-1)^T}z^{(i-1)}$\\ \> {\bf if} \= $i = 1$ \\ \> \> $p^{(1)} = z^{(0)}$ \\ \> {\bf else} \\ \> \>$\beta_{i-1} = \rho_{i-1} / \rho_{i-2} $ \\ \> \>$p^{(i)} = z^{(i-1)} + \beta_{i-1}p^{(i-1)} $ \\ \>{\bf endif} \\ \> $q^{(i)}=Ap^{(i)}$ \\ \>$\alpha_i = \rho_{i-1}/p^{(i)^T}q^{(i)}$ \\ \>$x^{(i)} = x^{(i-1)} + \alpha_ip^{(i)} $ \\ \>$r^{(i)} = r^{(i-1)} - \alpha_iq^{(i)} $ \\ \>check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:pcg} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $x^{(0)}+\mbox{span}\{r^{(0)},\ldots,A^{i-1}r^{(0)}\}$ } \newpage {\samepage \clearpage $(x^{(i)}-\hat{x})^TA(x^{(i)}-\hat{x})$ } \newpage {\samepage \clearpage $\hat{x}$ } \newpage {\samepage \clearpage $M\inv$ } \newpage {\samepage \clearpage $r^{(i)^T} M^{-1} r^{(j)} = 0$ } \newpage {\samepage \clearpage $\mbox{span}\{r^{(0)},\ldots,A^{i-1}r^{(0)}\}$ } \newpage {\samepage \clearpage $\{A^ix\}_{i\geq0}$ } \newpage {\samepage \clearpage $LU$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $\kappa_2$ } \newpage {\samepage \clearpage $M^{-1}A$ } \newpage {\samepage \clearpage $\lambda_{\max}$ } \newpage {\samepage \clearpage $\lambda_{\min}$ } \newpage {\samepage \clearpage $\kappa_2 (B) = \lambda_{\max}(B) / \lambda_{\min}(B) )$ } \newpage {\samepage \clearpage \begin{equation}% latex2html id marker 648 \label{cg_cond} \|x^{(i)} - \hat{x}\|_A \le 2 \alpha^i\|x^{(0)} - \hat{x}\|_A \end{equation} } \newpage {\samepage \clearpage % latex2html id marker 5171 $\alpha = (\sqrt{\kappa_2} - 1)/(\sqrt{\kappa_2}+1)$ } \newpage {\samepage \clearpage $\|y\|^2_A \equiv (y,Ay)$ } \newpage {\samepage \clearpage $\epsilon$ } \newpage {\samepage \clearpage $\sqrt{\kappa_2}$ } \newpage {\samepage \clearpage $\kappa_2 (A)=O(h^{-2})$ } \newpage {\samepage \clearpage $h^{-1}$ } \stepcounter{subsubsection} \stepcounter{subsubsection} \stepcounter{subsection} \newpage {\samepage \clearpage $2$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{displaymath} Ar^{(i)}=r^{(i+1)}t_{i+1,i}+r^{(i)}t_{i,i}+r^{(i-1)}t_{i-1,i}, \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} AR_i=R_{i+1}\bar{T}_i, \end{displaymath} } \newpage {\samepage \clearpage $\bar{T}_i$ } \newpage {\samepage \clearpage $(i+1) \times i$ } \newpage {\samepage \clearpage \begin{displaymath} \bar{T}_i= \begin{array}{cc} \begin{array}{ccc} \leftarrow & i &\rightarrow \end{array} & \begin{array}{c} \mbox{~~} \end{array} \\ \left( \begin{array}{cccc} \ddots & \ddots & & \\ \ddots & \ddots & \ddots & \\ & \ddots & \ddots & \ddots \\ & & \ddots & \ddots \\ & & & \ddots \end{array} \right) . & \begin{array}{c} \uparrow \\ \mbox{~} \\ i+1\\ \mbox{~} \\ \downarrow \end{array} \end{array} \end{displaymath} } \newpage {\samepage \clearpage $(\cdot ,\cdot )_A$ } \newpage {\samepage \clearpage \begin{displaymath} x^{(i)} \in \{r^{(0)}, Ar^{(0)}, \ldots, A^{i-1}r^{(0)}\},\mbox{~~}x^{(i)}=R_i\bar{y} \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} \|Ax^{(i)}-b\|_2 = \|AR_i\bar{y}-b\|_2 =\|R_{i+1}\bar{T}_iy-b\|_2 . \end{displaymath} } \newpage {\samepage \clearpage $D_{i+1} \equiv \mbox{diag} (\|r^{(0)}\|_2,\|r^{(1)}\|_2, ... , \|r^{(i)}\|_2)$ } \newpage {\samepage \clearpage $R_{i+1}D_{i+1}^{-1}$ } \newpage {\samepage \clearpage \begin{displaymath} \|Ax^{(i)}-b\|_2=\|D_{i+1}\bar{T}_iy-\|r^{(0)}\|_2e^{(1)}\|_2 \end{displaymath} } \newpage {\samepage \clearpage $(i+1,i)$ } \newpage {\samepage \clearpage $T_iy=\|r^{(0)}\|_2e^{(1)}$ } \newpage {\samepage \clearpage $T_i$ } \newpage {\samepage \clearpage $i \times i$ } \newpage {\samepage \clearpage $LQ$ } \stepcounter{subsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage $A^T A x = A^T b$ } \newpage {\samepage \clearpage \begin{displaymath} \left( \begin{array}{cc} I & A \\ A^T & 0 \end{array} \right) \left( \begin{array}{c} r \\ x \ \end{array} \right) = \left( \begin{array}{c} b \\ 0 \end{array} \right) . \end{displaymath} } \newpage {\samepage \clearpage $(p,A^TAp)$ } \newpage {\samepage \clearpage $(Ap,Ap)$ } \stepcounter{subsection} \newpage {\samepage \clearpage $\mbox{span}\{r^{(0)},Ar^{(0)},A^2r^{(0)},\ldots\}$ } \newpage {\samepage \clearpage \begin{tabbing}xxxxxx\= \kill \> $w^{(i)} = A v^{(i)}$ \\ \> {\bf for} \= $k = 1, \ldots , i$ \\ \> \> $w^{(i)} = w^{(i)} - (w^{(i)}, v^{(k)}) v^{(k)}$ \\ \> {\bf end} \\ \> $v^{(i+1)} = w^{(i)} / \| w^{(i)} \|$ \end{tabbing} } \newpage {\samepage \clearpage $\{A^kr^{(0)}\}$ } \newpage {\samepage \clearpage $(w^{(i)},v^{(k)})$ } \newpage {\samepage \clearpage $\|w^{(i)}\|$ } \newpage {\samepage \clearpage \begin{displaymath} x^{(i)}=x^{(0)}+y_1v^{(1)}+\cdots+y_iv^{(i)}, \end{displaymath} } \newpage {\samepage \clearpage $y_k$ } \newpage {\samepage \clearpage $\| b-Ax^{(i)} \|$ } \newpage {\samepage \clearpage $m$ } \newpage {\samepage \clearpage $(m)$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} $x^{(0)} $ is an initial guess \\ {\bf for} \= $j=1,2,....$ \\ \> Solve $r$ from $Mr=b-Ax^{(0)}$ \\ \> $v^{(1)}=r/\|r\|_2$ \\ \> $s:=\|r\|_2e_1$ \\ \> {\bf for} \= $i=1,2,...,m$ \\ \>\> Solve $w$ from $Mw=Av^{(i)}$ \\ \>\> {\bf for} \= $k=1,...,i$ \\ \>\>\> $h_{k,i}=(w,v^{(k)})$ \\ \>\>\> $w=w-h_{k,i}v^{(k)}$ \\ \>\> {\bf end} \\ \>\> $h_{i+1,i}=\|w\|_2$ \\ \>\> $v^{(i+1)}=w/h_{i+1,i}$ \\ \>\> apply $J_1 ,..., J_{i-1}$ on $(h_{1,i},...,h_{i+1,i})$ \\ \>\> construct $J_i$, acting on $i$th and $(i+1)$st component\\ \>\> of $h_{.,i}$, such that $(i+1)$st component of $J_ih_{.,i}$ is 0 \\ \>\> $s:=J_is$ \\ \>\> if $s(i+1)$ is small enough then (UPDATE($\tilde{x},i$) and quit) \\ \> {\bf end} \\ \> UPDATE($\tilde{x},m$) \\ \>check convergence; continue if necessary \\ {\bf end} \\ \mbox{~}\\ \mbox{In this scheme UPDATE($\tilde{x},i$)} \\ \mbox{replaces the following computations:} \\ \mbox{~} \\ Compute $y$ as the solution of $Hy=\tilde{s}$, in which \\ the upper $i \times i$ triangular part of $H$ has $h_{i,j}$ as \\ its elements (in least squares sense if $H$ is singular), \\ $\tilde{s}$ represents the first $i$ components of $s$ \\ $\tilde{x}=x^{(0)}+y_1 v^{(1)}+y_2 v^{(2)}+ . . . +y_i v^{(i)}$ \\ $s^{(i+1)} = \|b-A\tilde{x}\|_2$ \\ if $\tilde{x}$ is an accurate enough approximation then quit \\ else $x^{(0)}=\tilde{x}$ \end{tabbing} }} \label{fig:pgmres} \end{center} \end{figure} } \stepcounter{subsubsection} \stepcounter{subsubsection} \stepcounter{subsection} \newpage {\samepage \clearpage \begin{displaymath}% latex2html id marker 912 r^{(i)}=r^{(i-1)}-\alpha_iAp^{(i)},\qquad \tilde r^{(i)}=\tilde r^{(i-1)}-\alpha_iA^T\tilde p^{(i)}, \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} p^{(i)}=r^{(i-1)}+\beta_{i-1}p^{(i-1)},\qquad \tilde p^{(i)}=\tilde r^{(i-1)}+\beta_{i-1}\tilde p^{(i-1)}. \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}% latex2html id marker 931 \alpha_i={\tilde r^{(i-1)^T}r^{(i-1)}\over \tilde p^{(i)^T}Ap^{(i)}}, \qquad \beta_i={\tilde r^{(i)^T}r^{(i)}\over \tilde r^{(i-1)^T}r^{(i-1)}} \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} \tilde r^{(i)^T}r^{(j)}=\tilde p^{(i)^T}Ap^{(j)}=0\qquad \hbox{if $i\not=j$}. \end{displaymath} } \newpage {\samepage \clearpage \begin{figure}% latex2html id marker 950 [tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} xxxx\=xxxx\=xxxx\=xxxx\= \kill Compute $r^{(0)} = b - Ax^{(0)}$ for some initial guess $x^{(0)}$. \\ Choose $\tilde{r}^{(0)}$ (for example, $\tilde{r}^{(0)} = r^{(0)}$).\\ {\bf for } \= $ i = 1, 2, \ldots $ \\ \> solve $Mz^{(i-1)} = r^{(i-1)}$ \\ \> solve $M^T\tilde{z}^{(i-1)}=\tilde{r}^{(i-1)}$ \\ \> $\rho_{i-1}=z^{(i-1)^T}\tilde{r}^{(i-1)}$\\ \> {\bf if} $\rho_{i-1} = 0$, {\bf method fails} \\ \> {\bf if} $i = 1$ \\ \> \> $p^{(i)} = z^{(i-1)}$\\ \> \> $\tilde{p}^{(i)} = \tilde{z}^{(i-1)}$ \\ \> {\bf else} \\ \> \> $\beta_{i-1}=\rho_{i-1}/\rho_{i-2}$ \\ \> \> $p^{(i)} = z^{(i-1)} + \beta_{i-1} p^{(i-1)}$ \\ \> \> $\tilde{p}^{(i)} = \tilde{z}^{(i-1)} + \beta_{i-1} \tilde{p}^{(i-1)}$ \\ \> {\bf endif} \\ \> $q^{(i)} = Ap^{(i)}$ \\ \> $\tilde{q}^{(i)} = A^T \tilde{p}^{(i)}$ \\ \> $\alpha_i = \rho_{i-1} / \tilde{p}^{(i)^T} q^{(i)}$ \\ \> $x^{(i)} = x^{(i-1)} + \alpha_i p^{(i)}$ \\ \> $r^{(i)} = r^{(i-1)} - \alpha_i q^{(i)}$ \\ \> $\tilde{r}^{(i)} = \tilde{r}^{(i-1)} - \alpha_i \tilde{q}^{(i)}$ \\ \>check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:pbcg} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $z^{(i-1)^T}\tilde{r}^{(i-1)}\approx 0$ } \newpage {\samepage \clearpage $\tilde{p}^{(i)^T}q^{(i)}\approx 0$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $Ap^{(k)}$ } \newpage {\samepage \clearpage $A^T\tilde{p}^{(k)}$ } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{figure}% latex2html id marker 1063 [tp] \begin{center} \leavevmode \framebox[4.5in]{ \vbox{ \begin{tabbing} Compute $r^{(0)} = b - Ax^{(0)}$ for some initial guess $x^{(0)}$ \\ $\tilde{v}^{(1)} = r^{(0)}$; {\bf solve} $M_1 y = \tilde{v}^{(1)}$; $\rho_1 = \|y\|_2$ \\ Choose $\tilde{w}^{(1)}$ , for example $\tilde{w}^{(1)}=r^{(0)}$ \\ {\bf solve} $M_2^t z = \tilde{w}^{(1)}$; $\xi_1 =\|z\|_2 $\\ $\gamma_0 = 1; \eta_0 = -1$\\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \>{\bf if} $\rho_{i} = 0$ or $\xi_{i} = 0$ {\bf method fails} \\ \>$v^{(i)} = \tilde{v}^{(i)} / \rho_{i}$; $y=y/ \rho_{i}$ \\ \>$w^{(i)} = \tilde{w}^{(i)} / \xi_{i}$; $z=z/ \xi_{i}$ \\ \>$\delta_i=z^Ty$; {\bf if} $\delta_i = 0$ {\bf method fails} \\ \>{\bf solve } $M_2\tilde{y}=y$\\ \>{\bf solve } $M_1^T\tilde{z}=z$ \\ \> {\bf if } \= $i = 1$ \\ \> \> $p^{(1)} = \tilde{y}$; $q^{(1)} = \tilde{z}$ \\ \> \> {\bf else} \\ \> \>$p^{(i)} = \tilde{y} - (\xi_i\delta_i / \epsilon_{i-1})p^{(i-1)}$ \\ \> \>$q^{(i)} = \tilde{z} - (\rho_i\delta_i / \epsilon_{i-1})q^{(i-1)}$ \\ \> {\bf endif } \\ \> $\tilde{p}=Ap^{(i)}$ \\ \> $\epsilon_i = q^{(i)^T} \tilde{p}$; {\bf if} $\epsilon_i = 0 $ {\bf method fails} \\ \> $\beta_i = \epsilon_i / \delta_i$; {\bf if} $\beta_i = 0$ {\bf method fails} \\ \> $\tilde{v}^{(i+1)} = \tilde{p} - \beta_i v^{(i)}$ \\ \> {\bf solve} $M_1 y = \tilde{v}^{(i+1)}$ \\ \> $\rho_{i+1} = \|y\|_2$ \\ \> $\tilde{w}^{(i+1)} = A^Tq^{(i)} - \beta_i w^{(i)}$ \\ \> {\bf solve} $M_2^T z = \tilde{w}^{(i+1)}$ \\ \> $\xi_{i+1} = \|z\|_2$ \\ \> $\theta_i = \rho_{i+1} / (\gamma_{i-1}|\beta_i|)$; $\gamma_i = 1 / {\sqrt{1 + \theta_i^2}}$; {\bf if} $\gamma_i = 0$ {\bf method fails} \\ \> $\eta_i = -\eta_{i-1} \rho_i \gamma_i^2 / (\beta_i \gamma_{i-1}^2)$ \\ \> {\bf if } $i = 1$ \\ \> \> $d^{(1)} = \eta_1 p^{(1)}$; $s^{(1)} = \eta_1\tilde{p}$\\ \> {\bf else } \\ \> \>$d^{(i)} = \eta_i p^{(i)} + (\theta_{i-1}\gamma_i)^2 d^{(i-1)}$ \\ \> \>$s^{(i)}=\eta_i\tilde{p}+(\theta_{i-1}\gamma_i)^2s^{(i-1)}$ \\ \> {\bf endif } \\ \> $x^{(i)} = x^{(i-1)} + d^{(i)}$ \\ \> $r^{(i)} = r^{(i-1)} - s^{(i)}$ \\ \> check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \vspace{.1in}\\ \label{fig:pqmr} \end{center} \end{figure} } \stepcounter{subsubsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage $M = M_1M_2$ } \newpage {\samepage \clearpage $M_1=I$ } \newpage {\samepage \clearpage $\|r^{(i)}\|$ } \newpage {\samepage \clearpage $\sqrt{i+1}$ } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{equation} \label{eqn:cgs} r^{(i)} = P_i(A)r^{(0)}. \end{equation} } \newpage {\samepage \clearpage $\widetilde{r}^{(i)}=P_i(A^T)\widetilde{r}^{(0)}$ } \newpage {\samepage \clearpage \begin{equation} \label{eqn:cgs2} \rho_i = (\tilde{r}^{(i)},r^{(i)}) = (P_i(A^T)\tilde{r}^{(0)}, P_i(A)r^{(0)}) = (\tilde{r}^{(0)},P_i^2(A)r^{(0)}). \end{equation} } \newpage {\samepage \clearpage $P_i(A)$ } \newpage {\samepage \clearpage $P_i^2(A)r^{(0)}$ } \newpage {\samepage \clearpage \begin{figure}% latex2html id marker 1233 [tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Compute $r^{(0)} = b - Ax^{(0)}$ for some initial guess $x^{(0)}$ \\ Choose $\tilde{r}$ (for example, $\tilde{r} = r^{(0)}$) \\ {\bf for } \= $ i = 1, 2, \ldots $ \\ \>$ \rho_{i-1} = \tilde{r}^Tr^{(i-1)} $ \\ \>{\bf if} $\rho_{i-1} = 0$ {\bf method fails} \\ \> {\bf if } \= $i = 1$ \\ \>\> $u^{(1)}=r^{(0)}$ \\ \>\> $p^{(1)}=u^{(1)}$ \\ \> {\bf else } \\ \>\> $\beta_{i-1} = \rho_{i-1} / \rho_{i-2}$ \\ \>\> $ u^{(i)} = r^{(i-1)} + \beta_{i-1} q^{(i-1)} $ \\ \>\> $ p^{(i)} = u^{(i)} + \beta_{i-1} (q^{(i-1)} + \beta_{i-1} p^{(i-1)})$ \\ \> {\bf endif } \\ \> {\bf solve} $M\hat{p} = p^{(i)} $ \\ \> $ \hat{v} = A\hat{p} $ \\ \> $ \alpha_i = \rho_{i-1} / \tilde{r}^T\hat{v} $ \\ \> $ q^{(i)} = u^{(i)} - \alpha_i \hat{v} $ \\ \> {\bf solve} $M\hat{u} = u^{(i)} + q^{(i)} $ \\ \> $x^{(i)}=x^{(i-1)}+\alpha_i \hat{u}$ \\ \> $\hat{q}=A\hat{u}$ \\ \> $r^{(i)} = r^{(i-1)} - \alpha_i \hat{q} $ \\ \> check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:pcgs} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $r^{(k)} = P_k(A)r^{(0)}$ } \stepcounter{subsubsection} \stepcounter{subsection} \newpage {\samepage \clearpage $i\mapsto P_i^2(A)r^{(0)}$ } \newpage {\samepage \clearpage $i\mapsto Q_i(A)P_i(A)r^{(0)}$ } \newpage {\samepage \clearpage $Q_i$ } \newpage {\samepage \clearpage \begin{figure}% latex2html id marker 1320 [tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Compute $r^{(0)} = b - Ax^{(0)}$ for some initial guess $x^{(0)}$ \\ Choose $\tilde{r}$ (for example, $\tilde{r} = r^{(0)}$) \\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \>$\rho_{i-1} = \tilde{r}^Tr^{(i-1)}$ \\ \> {\bf if} $\rho_{i-1} = 0$ {\bf method fails} \\ \> {\bf if} \= $i = 1$ \\ \>\> $p^{(i)}=r^{(i-1)}$ \\ \> {\bf else} \\ \>\> $\beta_{i-1} = (\rho_{i-1}/\rho_{i-2})(\alpha_{i-1}/\omega_{i-1})$ \\ \>\> $p^{(i)} = r^{(i-1)} + \beta_{i-1} (p^{(i-1)} - \omega_{i-1}v^{(i-1)})$ \\ \> {\bf endif} \\ \>{\bf solve} $M\hat{p} = p^{(i)}$ \\ \>$v^{(i)} = A\hat{p}$ \\ \>$\alpha_i = \rho_{i-1}/\tilde{r}^Tv^{(i)}$ \\ \>$s = r^{(i-1)} - \alpha_i v^{(i)}$ \\ \>check norm of $s$; if small enough: set $x^{(i)}=x^{(i-1)}+\alpha_i\hat{p}$ and stop \\ \>{\bf solve} $M\hat{s} = s$ \\ \>$t = A\hat{s}$ \\ \>$\omega_i = t^Ts/t^Tt$ \\ \>$x^{(i)} = x^{(i-1)} + \alpha_i \hat{p} + \omega_i\hat{s}$ \\ \>$r^{(i)} = s - \omega_i t$ \\ \>check convergence; continue if necessary \\ \> for continuation it is necessary that $\omega_i \neq 0$ \\ {\bf end} \end{tabbing} }} \label{fig:pbcgstab} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $\omega_i$ } \newpage {\samepage \clearpage $s$ } \stepcounter{subsubsection} \stepcounter{subsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage $d > 0$ } \newpage {\samepage \clearpage $d + c$ } \newpage {\samepage \clearpage $d - c$ } \newpage {\samepage \clearpage $r$ } \newpage {\samepage \clearpage \begin{equation}\label{eqn:minr} r = {a + \sqrt{a^2 - c^2}\over {d + \sqrt{d^2 - c^2}}}, \end{equation} } \newpage {\samepage \clearpage $a$ } \newpage {\samepage \clearpage $[ \lambda _{min}, \lambda _{max} ] $ } \stepcounter{subsubsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage $w$ } \newpage {\samepage \clearpage $p$ } \newpage {\samepage \clearpage \begin{figure}% latex2html id marker 1448 [tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Compute $r^{(0)} = b - Ax^{(0)}$ for some initial guess $x^{(0)}$.\\ $d=(\lambda_{\max}+\lambda_{\min})/2$, $c=(\lambda_{\max}-\lambda_{\min})/2$. \\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \>{\bf solve} $Mz^{(i-1)} = r^{(i)} $.\\ \> {\bf if } \= $i = 1$ \\ \>\> $p^{(1)}=z^{(0)} $ \\ \>\> $\alpha_1=2/d$ \\ \> {\bf else} \\ \>\> $\beta_{i-1}=\alpha_{i-1}(c/2)^2$\\ \>\> $\alpha_i=1/(d-\beta_{i-1})$ \\ \>\> $ p^{(i)} = z^{(i-1)} + \beta_{i-1}p^{(i-1)} $.\\ \> {\bf endif } \\ \> $x^{(i)} = x^{(i-1)} + \alpha_ip^{(i)} $.\\ \> $r^{(i)} = b - Ax^{(i)} \mbox{~~~}(=r^{(i-1)}-\alpha_iAp^{(i)})$.\\ \> check convergence; continue if necessary \\ {\bf end} \end{tabbing} }} \label{fig:pcheby} \end{center} \end{figure} } \stepcounter{section} \newpage {\samepage \clearpage \begin{table}[tv] \begin{minipage}{\textwidth} \begin{center} \begin{tabular}{|l|c|c|c|c|} \hline & & & Matrix- & \\ & Inner & & Vector & Precond \\ Method & Product & {\tt SAXPY} & Product & Solve \\ \hline JACOBI & & & $1^a$\footnotetext[1]{This method performs no real matrix vector product or preconditioner solve, but the number of operations is equivalent to a matrix-vector multiply.} & \\ GS & & 1 & $1^a$ & \\ SOR & & 1 & $1^a$ & \\ CG & 2 & 3 & 1 & 1 \\ GMRES & $i+1$ & $i+1$ & 1 & 1 \\ BiCG & 2 & 5 & 1/1 & 1/1 \\ QMR & 2 & 8+$4^{bc}$\footnotetext[2]{True {\tt SAXPY} operations $+$ vector scalings.}\footnotetext[3]{Less for implementations that do not recursively update the residual.} & 1/1 & 1/1 \\ CGS & 2 & 6 & 2 & 2 \\ Bi-CGSTAB & 4 & 6 & 2 & 2 \\ CHEBYSHEV & & 2 & 1 & 1 \\ \hline \end{tabular}\end{center} \label{perf_ops_tbl} \end{minipage} \end{table} } \newpage {\samepage \clearpage \begin{table}[tv] \begin{minipage}{\textwidth} \begin{center} \begin{tabular}{|l|c|} \hline Method & Storage \\ & Reqmts \\ \hline JACOBI & $\mbox{matrix} + 3n$ \\ SOR & $\mbox{matrix} + 2n$ \\ CG & $\mbox{matrix} + 6n$ \\ GMRES & $\mbox{matrix} + (i+5)n$ \\ BiCG & $\mbox{matrix} + 10n$ \\ CGS & $\mbox{matrix} + 11n$ \\ Bi-CGSTAB &$\mbox{matrix} + 10n$ \\ QMR & $\mbox{matrix} + 16n^c$\footnotetext[3]{Less for implementations that do not recursively update the residual.} \\ CHEBYSHEV & $\mbox{matrix} + 5n$ \\ \hline \end{tabular} \label{store_tbl} \end{center} \end{minipage} \end{table} } \newpage {\samepage \clearpage $\omega > 1$ } \stepcounter{section} \stepcounter{section} \newpage {\samepage \clearpage $T$ } \stepcounter{chapter} \stepcounter{section} \newpage {\samepage \clearpage \begin{displaymath} M^{-1}Ax=M^{-1}b \end{displaymath} } \newpage {\samepage \clearpage $A\inv$ } \stepcounter{subsection} \stepcounter{subsection} \newpage {\samepage \clearpage $A\rightarrow M^{-1}A$ } \newpage {\samepage \clearpage $M^{-1}$ } \newpage {\samepage \clearpage \begin{displaymath} M_1^{-1} AM_2\inv(M_2x)=M_1^{-1} b. \end{displaymath} } \newpage {\samepage \clearpage $M_1=M_2^t$ } \newpage {\samepage \clearpage \begin{displaymath} \mbox{solve $u$ from $Mu = v$}, \end{displaymath} } \newpage {\samepage \clearpage $M_1$ } \newpage {\samepage \clearpage $M_2$ } \newpage {\samepage \clearpage $r_0\leftarrow M_1^{-1}r_0$ } \newpage {\samepage \clearpage $x_n\leftarrow M_2^{-1}x_n$ } \newpage {\samepage \clearpage $I$ } \newpage {\samepage \clearpage $\ncofm$ } \newpage {\samepage \clearpage \begin{displaymath}r_0\leftarrow M_1^{-1}r_0\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}x\leftarrow M_2^{-1}x\end{displaymath} } \newpage {\samepage \clearpage $M_1=\nobreak I$ } \stepcounter{section} \newpage {\samepage \clearpage \begin{displaymath} m_{i,j} = \left\{ \begin{array}{ll} a_{i,i} & \mbox{if $i=j$} \\ 0 & \mbox{otherwise}. \end{array} \right. \end{displaymath} } \stepcounter{subsection} \newpage {\samepage \clearpage $S=\{1,\ldots,n\}$ } \newpage {\samepage \clearpage $S=\bigcup_i S_i$ } \newpage {\samepage \clearpage $S_i$ } \newpage {\samepage \clearpage \begin{displaymath} m_{i,j} = \left\{ \begin{array}{ll} a_{i,j} & \mbox{if $i$ and $j$ are in the same index subset} \\ 0 & \mbox{otherwise}. \end{array} \right. \end{displaymath} } \stepcounter{subsection} \stepcounter{section} \newpage {\samepage \clearpage $P_n(x)=x^n$ } \newpage {\samepage \clearpage \begin{displaymath} A=D+L+L^T \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} M=(D+L)D^{-1} (D+L)^T, \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} M(\omega)={1\over 2-\omega}({1\over\omega}D+L) ({1\over\omega}D)^{-1}({1\over\omega}D+L)^T. \end{displaymath} } \newpage {\samepage \clearpage $\kappa(M_{\omega_{\rm opt}}^{-1} A)=O(\sqrt{\kappa(A)})$ } \stepcounter{section} \newpage {\samepage \clearpage $M=LU$ } \stepcounter{subsection} \newpage {\samepage \clearpage % latex2html id marker 6031 $A+\alpha I$ } \newpage {\samepage \clearpage % latex2html id marker 6033 $\alpha$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $Mx=y$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Let $M=LU$ and $y$ be given.\\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \> $z_i=\ell_{ii}^{-1}(y_i-\sum_{j $x_i=u_{ii}^{-1}(z_i-\sum_{j>i}u_{ij}x_j)$ \end{tabbing} }} \label{fig:lu-solv} \end{center} \end{figure} } \newpage {\samepage \clearpage $M=(D+L)D^{-1}(D+U)$ } \newpage {\samepage \clearpage \begin{displaymath} (D+L)z=y,\qquad (I+D^{-1} U)x=z\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} (I+LD^{-1})z=y,\qquad (D+U)x=z.\end{displaymath} } \newpage {\samepage \clearpage $D\inv$ } \newpage {\samepage \clearpage $M=(D+L)D^{-1}(D+U)=(D+L)(I+D^{-1} U)$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Let $M=(D+L)(I+D^{-1} U)$ and $y$ be given.\\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \> $z_i=d_{ii}^{-1}(y_i-\sum_{j $x_i=z_i-d_{ii}^{-1}\sum_{j>i}u_{ij}x_j$ \end{tabbing} }} \label{fig:ldu-solv} \end{center} \end{figure} } \newpage {\samepage \clearpage $LD\inv$ } \newpage {\samepage \clearpage $D^{-1} U$ } \stepcounter{subsection} \newpage {\samepage \clearpage $S$ } \newpage {\samepage \clearpage $(i,j)$ } \newpage {\samepage \clearpage $a_{i,j}\not=0$ } \newpage {\samepage \clearpage $ILU(0)$ } \newpage {\samepage \clearpage $k+1$ } \newpage {\samepage \clearpage \begin{displaymath} \mbox{for each $k$, $i,j>k$:}\quad a_{i,j}\leftarrow \left\{ \begin{array}{ll} a_{i,j}-a_{i,k}a_{k,k}^{-1} a_{k,j} & \mbox{if $(i,j)\in S$} \\ a_{i,j} & \mbox{otherwise}. \end{array} \right. \end{displaymath} } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{equation} {\rm fill}(i,j)=1+\max\{{\rm fill}(i,k),{\rm fill}(k,i)\}. \label{eq:fill-def}\end{equation} } \newpage {\samepage \clearpage $a_{ij}$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $ILU$ } \newpage {\samepage \clearpage $A=D_A+L_A+U_A$ } \newpage {\samepage \clearpage $M=(D+L_A)\allowbreak D^{-1}(D+\nobreak U_A)$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Let $S$ be the nonzero set $\{(i,j)\colon a_{ij}\not=0\}$\\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \> {\bf set} $d_{ii}\leftarrow a_{ii}$ \\ {\bf for } \= $ i = 1, 2, \ldots$ \\ \> {\bf set} $d_{ii}\leftarrow 1/d_{ii}$ \\ \> {\bf for } \= $ j = i+1, i+2, \ldots$ \\ \> \> if $(i,j)\in S$ and $(j,i)\in S$ then \\ \> \> {\bf set} $d_{jj}\leftarrow d_{jj}-a_{ji}d_{ii}a_{ij}$ \end{tabbing} }} \label{fig:d-ilu} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $(i-1,j)$ } \newpage {\samepage \clearpage $(i,j-1)$ } \newpage {\samepage \clearpage \begin{displaymath} d_{i,i}=\left\{ \begin{array}{ll} a_{1,1} & \mbox{if $i=1$} \\ a_{i,i}-a_{i,i-1}d_{i-1}^{-1} a_{i-1,i} & \mbox{if $1 Initially: $d_{i,i}=a_{i,i}$ for all $i$ \\ \> {\bf for} \= $i=1..nm$ do: \\ \> \> $\left\{ \begin{array}{ll} d_{i+1,i+1}=d_{i+1,i+1}-a_{i+1,i}d_{i,i}^{-1} a_{i,i+1} & \mbox{if there is no $k$} \\ & \mbox{such that $i=kn$} \\ d_{i+n,i+n}=d_{i+n,i+n}-a_{i+n,i}d_{i,i}^{-1} a_{i,i+n} & \mbox{if $i+n\leq nm$} \end{array} \right.$ \end{tabbing} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $a_{i,k}a_{k,k}^{-1} a_{k,j}$ } \newpage {\samepage \clearpage $a_{i,i}$ } \newpage {\samepage \clearpage $O(h^{-2})$ } \newpage {\samepage \clearpage $A+O(h^2)D_A$ } \newpage {\samepage \clearpage $\kappa(M^{-1} A)=O(h^{-1})$ } \newpage {\samepage \clearpage \begin{displaymath} x_0=M^{-1} b\end{displaymath} } \newpage {\samepage \clearpage $r_0$ } \newpage {\samepage \clearpage $r_i$ } \newpage {\samepage \clearpage % latex2html id marker 6285 $0<\alpha<\nobreak1$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $n\times n$ } \newpage {\samepage \clearpage $(D+L)x=u$ } \newpage {\samepage \clearpage $n\times\nobreak n$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} {\bf for } \= $ k = 1, \ldots,2n-1$ \\ \> {\bf do} \= {\bf in parallel for } $ i = \max(1,k+1-n),\min(n,k)$\\ \> \> $j=k-i+1$\\ \> \> $x_{i+(j-1)n}\leftarrow $ \= $ D_{i+(j-1)n}y_{i+(j-1)n}$ \\ \> \> \> $-L_{i+(j-1)n}{i-1+(j-1)n}x_{i-1+(j-1)n}$ \\ \> \> \> $-L_{i+(j-1)n}{i+(j-2)n}x_{i+(j-2)n}$ \end{tabbing} }} \label{fig:wave-solve} \end{center} \end{figure} } \newpage {\samepage \clearpage $i+j=k$ } \newpage {\samepage \clearpage $i+j=k-1$ } \newpage {\samepage \clearpage $I-L$ } \newpage {\samepage \clearpage \begin{equation} (I-L)^{-1} = \cases{I+L+L^2+L^3+\cdots\cr (I+L)(I+L^2)(I+L^4)\cdots} \label{eq:IL-expansions}\end{equation} } \newpage {\samepage \clearpage $L_A$ } \newpage {\samepage \clearpage \begin{displaymath} A=D_A+L_A+U_A,\qquad M=(D+L_A)D^{-1}(D+U_A),\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} M=(I+L)D(I+U),\qquad \hbox{where $L=L_AD\inv$, $U=D^{-1} U_A$}.\end{displaymath} } \newpage {\samepage \clearpage $L_AD\inv$ } \newpage {\samepage \clearpage $M^{(p)}\approx M\inv$ } \newpage {\samepage \clearpage $M=(I+L)D(I+U)$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Let $M=(I+L)D(I+U)$ and $y$ be given.\\ $t\leftarrow y$\\ {\bf for } \= $ k = 1, \ldots,p$ \\ \> $t\leftarrow y-Lt$ \\ $x\leftarrow D^{-1} t$, $t\leftarrow x$ \\ {\bf for } \= $ k = 1, \ldots,p$ \\ \> $x\leftarrow t-Ux$ \end{tabbing} }} \label{fig:lu-neuman} \end{center} \end{figure} } \newpage {\samepage \clearpage $L=L_AD\inv$ } \newpage {\samepage \clearpage $U=D^{-1} U_A$ } \newpage {\samepage \clearpage \begin{equation} M^{(p)}=\sum_{k=0}^p(-U)^pD^{-1}\sum_{k=0}^p(-L)^p, \label{eq:M-exp}\end{equation} } \newpage {\samepage \clearpage $x=M^{(p)}y$ } \stepcounter{subsubsection} \stepcounter{subsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} {\bf for} \= $i=1,2,\dots$ \\ \> $X_i\leftarrow A_{ii}$ \\ {\bf for} \= $i=1,2,\dots$ \\ \> Let $Y_i\approx X_i\inv$ \\ \> {\bf for} \= $j=i+1,i+2,\ldots$ \\ \> \> if $A_{ij}\not=0$ and $A_{ji}\not=0$, \\ \> \> then $X_j\leftarrow X_j-A_{ji}Y_iA_{ij}$ \end{tabbing} }} \label{fig:blu-fac} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $d_{i,i}=1/a_{i,i}$ } \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} Let $X$ be a banded matrix,\\ factor $X=(I+L)D^{-1}(I+U)$,\\ let $Y=(I-U)D(I-L)$ \end{tabbing} }} \label{fig:apx-inv} \end{center} \end{figure} } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{figure}[tp] \begin{center} \leavevmode \framebox[4.5in]{\vbox{ \begin{tabbing} $X_1=A_{1,1}$ \\ {\bf for} \= $i \geq 1$ \\ \> let $Y_i\approx X_i\inv$ \\ \> $X_{i+1}=A_{i+1,i+1}-A_{i+1,i}Y_iA_{i,i+1}$ \end{tabbing} }} \label{fig:blu-fac-tri} \end{center} \end{figure} } \newpage {\samepage \clearpage $(A_{i,i})$ } \newpage {\samepage \clearpage $X_i$ } \newpage {\samepage \clearpage $Y_i$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{displaymath} A=(D+L)D^{-1}(D+U)=(D+L)(I+D^{-1} U) \end{displaymath} } \newpage {\samepage \clearpage $(I+L_AD^{-1})(D+U_A)$ } \newpage {\samepage \clearpage $U_Q$ } \newpage {\samepage \clearpage $X={\rm diag}(X_i)$ } \newpage {\samepage \clearpage \begin{displaymath} M=(X+L)(I+X^{-1} U) \end{displaymath} } \newpage {\samepage \clearpage $Y={\rm diag}(Y_i)$ } \newpage {\samepage \clearpage \begin{displaymath} M=(Y\inv+L)(I+YU). \end{displaymath} } \stepcounter{subsection} \stepcounter{subsection} \newpage {\samepage \clearpage $L^{-1}AA^TL^{-T}y=b$ } \stepcounter{section} \newpage {\samepage \clearpage $A=I-B$ } \newpage {\samepage \clearpage $A^{-1}=\sum_{k=0}^\infty B^k$ } \newpage {\samepage \clearpage $A=M-N$ } \newpage {\samepage \clearpage \begin{displaymath} M_p^{-1}=(\sum_{i=0}^{p-1}(I-M^{-1} A)^i)M^{-1} . \end{displaymath} } \newpage {\samepage \clearpage $kp$ } \newpage {\samepage \clearpage $M=P_n(A)$ } \newpage {\samepage \clearpage $P(0)=1$ } \newpage {\samepage \clearpage $\|I-M^{-1} A\|$ } \newpage {\samepage \clearpage $\max_i\sum_j|A_{i,j}|$ } \stepcounter{section} \stepcounter{subsection} \newpage {\samepage \clearpage $(A+A^T)/2$ } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{displaymath} c_1\leq{x^TAx\over x^TBx}\leq c_2\quad\hbox{for all $x$}, \end{displaymath} } \newpage {\samepage \clearpage $c_1$ } \newpage {\samepage \clearpage $c_2$ } \newpage {\samepage \clearpage \begin{displaymath} -\Delta(u_{n+1}-u_n)=-({\cal L}u_n-f).\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} -(a(x,y)u_x)_x-(b(x,y)u_y)_y=f, \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} -(\tilde a(x)u_x)_x-(\tilde b(y)u_y)_y=f. \end{displaymath} } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{displaymath} {\cal L}={\cal L}_1+{\cal L}_2,\qquad \hbox{where ${\cal L}_1=-{\partial^2\over \partial x^2}$, ${\cal L}_2=-{\partial^2\over \partial y^2}$}. \end{displaymath} } \newpage {\samepage \clearpage $L_1$ } \newpage {\samepage \clearpage $L_2$ } \newpage {\samepage \clearpage ${\cal L}_1$ } \newpage {\samepage \clearpage ${\cal L}_2$ } \newpage {\samepage \clearpage $L_1+L_2=(I+L_1)(I+L_2)-I-L_1L_2$ } \newpage {\samepage \clearpage \begin{displaymath}% latex2html id marker 2220 (1+\alpha L_1) (1+\alpha L_2)u^{(m+1)} = \left[(1+\beta L_1) (1+\beta L_2)\right]u^{(m)} \end{displaymath} } \newpage {\samepage \clearpage % latex2html id marker 6531 $\alpha$ } \newpage {\samepage \clearpage $\beta$ } \newpage {\samepage \clearpage $u^{(m)}$ } \newpage {\samepage \clearpage % latex2html id marker 6545 $I+\alpha L_1$ } \newpage {\samepage \clearpage $P_x\times P_y$ } \stepcounter{chapter} \stepcounter{section} \newpage {\samepage \clearpage $A^HAx=A^Hb$ } \newpage {\samepage \clearpage $(x,y)=\bar x^Ty$ } \newpage {\samepage \clearpage $(x,y)=x^Ty$ } \newpage {\samepage \clearpage $x^Tx=0$ } \newpage {\samepage \clearpage $x\not =0$ } \stepcounter{section} \newpage {\samepage \clearpage $\delta A$ } \newpage {\samepage \clearpage $\delta b$ } \newpage {\samepage \clearpage $(A+\delta A)x^{(i)}=b+\delta b$ } \newpage {\samepage \clearpage $\{x^{(i)}\}$ } \newpage {\samepage \clearpage $e^{(i)} \equiv x^{(i)} - x$ } \newpage {\samepage \clearpage $maxit$ } \newpage {\samepage \clearpage $\|b\|$ } \newpage {\samepage \clearpage $\|A\|$ } \newpage {\samepage \clearpage $b$ } \newpage {\samepage \clearpage $r^{(i)} = Ax^{(i)}-b$ } \newpage {\samepage \clearpage $ 10^{-6}$ } \newpage {\samepage \clearpage $\pm 10^{-6} \|A\|$ } \newpage {\samepage \clearpage $\pm 10^{-6} \|b\|$ } \newpage {\samepage \clearpage $\varepsilon$ } \newpage {\samepage \clearpage $\varepsilon = 2^{-24} \approx 10^{-7}$ } \newpage {\samepage \clearpage $\varepsilon = 2^{-53} \approx 10^{-16}$ } \newpage {\samepage \clearpage \begin{tabbing}junkjunk \= junk \= junk \= junk \= junk \= junk \kill \> $i=0$ \\ \> {\bf repeat} \\ \> \> $i = i + 1$ \\ \> \> Compute the approximate solution $x^{(i)}$. \\ \> \> Compute the residual $r^{(i)} = Ax^{(i)} - b$. \\ \> \> Compute $\|r^{(i)}\|$ and $\|x^{(i)}\|$. \\ \> {\bf until} $i \geq maxit$ or $\|r^{(i)}\| \leq {\em stop\_tol} \cdot ( \|A\| \cdot \| x^{(i)} \| + \|b\| )$. \end{tabbing} } \newpage {\samepage \clearpage $\| x^{(i)} \|$ } \newpage {\samepage \clearpage \begin{tabbing}junkjunk \= junk \= junk \= junk \= junk \= junk \kill \> {\bf until} $i \geq maxit$ or $\|r^{(i)}\| \leq {\em stop\_tol} \cdot \|b\| \; \; .$ \end{tabbing} } \newpage {\samepage \clearpage $\|e^{(i)}\| \leq \| A^{-1} \| \cdot \|r^{(i)}\|$ } \newpage {\samepage \clearpage $\|A^{-1}\|$ } \newpage {\samepage \clearpage \begin{tabbing}junkjunk \= junk \= junk \= junk \= junk \= junk \kill \> {\bf until} $i \geq maxit$ or $\|r^{(i)}\| \leq {\em stop\_tol} \cdot \|x^{(i)}\| / \|A^{-1}\| \; \; ,$ \end{tabbing} } \newpage {\samepage \clearpage $\|e^{(i)}\| / \|x^{(i)}\|$ } \stepcounter{subsection} \newpage {\samepage \clearpage $e^{(i)} = x^{(i)} - x$ } \newpage {\samepage \clearpage $e^{(i)}$ } \newpage {\samepage \clearpage \begin{displaymath} \begin{array}{lcl} \|x\|_{\infty} & \equiv & \max_j |x_j| \; , \\ \|x\|_{1} & \equiv & \sum_j |x_j| \; {\rm, and} \\ \|x\|_{2} & \equiv & ( \sum_j |x_j|^2 )^{1/2} \; \; . \end{array} \end{displaymath} } \newpage {\samepage \clearpage % latex2html id marker 6697 $\|x\|_{B,\alpha} \equiv \|Bx\|_{\alpha}$ } \newpage {\samepage \clearpage % latex2html id marker 6701 $\alpha$ } \newpage {\samepage \clearpage $\infty$ } \newpage {\samepage \clearpage \begin{displaymath} \begin{array}{lcl} \|A\|_{\infty} & \equiv & \max_j \sum_k |a_{j,k}| \; , \\ \|A\|_{1} & \equiv & \max_k \sum_j |a_{j,k}| \; {\rm, and} \\ \|A\|_{F} & \equiv & ( \sum_{jk} |a_{j,k}|^2 )^{1/2} \; \; , \end{array} \end{displaymath} } \newpage {\samepage \clearpage % latex2html id marker 6709 $\|A\|_{B, \alpha} \equiv \|BAB^{-1}\|_{\alpha}$ } \newpage {\samepage \clearpage $\|A\|_2 = ( \lambda_{\max} ( AA^T ) )^{1/2}$ } \newpage {\samepage \clearpage $\|x\|$ } \newpage {\samepage \clearpage $\|x\|_2$ } \newpage {\samepage \clearpage $\|A\|_F$ } \newpage {\samepage \clearpage $\|A\|_2$ } \newpage {\samepage \clearpage $\|x+y\| \leq \|x\| + \|y\|$ } \newpage {\samepage \clearpage $\|A+B\| \leq \|A\| + \|B\|$ } \newpage {\samepage \clearpage $\|Ax\| \leq \|A\| \cdot \|x\|$ } \newpage {\samepage \clearpage $\|x\|_{\infty} \leq 1$ } \newpage {\samepage \clearpage $\sqrt{n}$ } \newpage {\samepage \clearpage $\|x\|_1$ } \newpage {\samepage \clearpage $\|e^{(i)}\|$ } \newpage {\samepage \clearpage $\max\{ \|\delta A\| / \|A\|, \|\delta b\| / \|b\| \}$ } \newpage {\samepage \clearpage $(A+ \delta A) x^{(i)} = (b+ \delta b)$ } \newpage {\samepage \clearpage $\delta$ } \newpage {\samepage \clearpage \begin{displaymath} e^{(i)} = x^{(i)} - x = A^{-1}(Ax^{(i)} - b) = A^{-1} r^{(i)}, \end{displaymath} } \newpage {\samepage \clearpage $\|r^{(i)}\| \le \tau$ } \newpage {\samepage \clearpage $\|e^{(i)}\| \leq \tau \cdot \|A^{-1}\|$ } \newpage {\samepage \clearpage $\| e^{(i)} \| \leq \| \, |A^{-1}| \cdot |r^{(i)}| \, \|$ } \newpage {\samepage \clearpage $|X|$ } \newpage {\samepage \clearpage $X$ } \newpage {\samepage \clearpage $\| \delta A \| \leq \varepsilon \|A\|$ } \newpage {\samepage \clearpage $\| \delta b \| \leq \varepsilon \|b\|$ } \newpage {\samepage \clearpage $\|r^{(i)}\| \leq S_1 \equiv {\em stop\_tol} \cdot ( \|A\| \cdot \|x^{(i)}\| + \|b\|)$ } \newpage {\samepage \clearpage $\| \delta A \| \leq {\em stop\_tol} \cdot \|A\|$ } \newpage {\samepage \clearpage $\| \delta b \| \leq {\em stop\_tol} \cdot \|b\|$ } \newpage {\samepage \clearpage \begin{displaymath} \|e^{(i)}\| \leq \| A^{-1} \| \cdot \|r^{(i)} \| \leq {\em stop\_tol} \cdot \|A^{-1}\| \cdot ( \|A\| \cdot \|x^{(i)}\| + \|b\|) \; . \end{displaymath} } \newpage {\samepage \clearpage $\|r^{(i)}\| \leq S_2 \equiv {\em stop\_tol} \cdot \|b\|$ } \newpage {\samepage \clearpage $\delta A =0$ } \newpage {\samepage \clearpage $\| \delta b \| \leq tol \cdot \|b\|$ } \newpage {\samepage \clearpage $\|A\| \cdot \|x\| \gg \|b\|$ } \newpage {\samepage \clearpage \begin{displaymath}1 \ll \frac{\|A\| \cdot \|x\|}{\|b\|} = \frac{\|A\| \cdot \| A^{-1} b\|}{\|b\|} \leq \|A\| \cdot \|A^{-1}\| \; \; .\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}\|e^{(i)}\| \leq \| A^{-1} \| \cdot \| r^{(i)} \| \leq {\em stop\_tol} \cdot \|A^{-1}\| \cdot \|b\|\end{displaymath} } \newpage {\samepage \clearpage $\|A^{-1}\| \cdot \|r^{(i)}\|$ } \newpage {\samepage \clearpage $\|r^{(i)}\| \leq S_3 \equiv {\em stop\_tol} \cdot \|x^{(i)}\| / \| A^{-1} \|$ } \newpage {\samepage \clearpage \begin{displaymath}\frac{\|e^{(i)}\|}{\|x^{(i)}\|} \leq \frac{\|A^{-1}\| \cdot \|r^{(i)}\|}{\|x^{(i)}\|} \leq {\em stop\_tol} \; \; ,\end{displaymath} } \newpage {\samepage \clearpage $\| \delta A\|$ } \newpage {\samepage \clearpage $\| \delta b \|$ } \newpage {\samepage \clearpage $\delta a_{j,k}$ } \newpage {\samepage \clearpage $\delta b_j$ } \newpage {\samepage \clearpage $S_4 \equiv \max_j ( |r^{(i)}|_j / (E \cdot |x^{(i)}| + f)_j ) \leq {\em stop\_tol}$ } \newpage {\samepage \clearpage $E$ } \newpage {\samepage \clearpage $f$ } \newpage {\samepage \clearpage $|z|$ } \newpage {\samepage \clearpage $| \delta a_{j,k} | \leq tol \cdot e_{j,k}$ } \newpage {\samepage \clearpage $| \delta b_{j} | \leq tol \cdot f_{j}$ } \newpage {\samepage \clearpage $e_{j,k} = \|A\|_{\infty}$ } \newpage {\samepage \clearpage $f_j=\|b\|_{\infty}$ } \newpage {\samepage \clearpage $\|r^{(i)}\|_{\infty} / (n \|A\|_{\infty} \|x^{(i)}\|_{\infty} + \|b\|_{\infty})$ } \newpage {\samepage \clearpage $e_{j,k} = |a_{j,k}|$ } \newpage {\samepage \clearpage $f_j = |b_j|$ } \newpage {\samepage \clearpage \begin{displaymath}\| e^{(i)} \|_{\infty} \leq \| \, |A^{-1}| \cdot |r^{(i)}| \, \| \leq S_4 \cdot \| \, |A^{-1}| ( E |x^{(i)}| + f ) \|_{\infty}\end{displaymath} } \newpage {\samepage \clearpage $A^{-1}$ } \newpage {\samepage \clearpage $\|r^{(i)}\| \leq S_5 \equiv {\em stop\_tol} \cdot \|r^{(0)}\|$ } \newpage {\samepage \clearpage $x^{(0)}$ } \newpage {\samepage \clearpage $x^{(0)} = 0$ } \newpage {\samepage \clearpage $r^{(0)} = b$ } \newpage {\samepage \clearpage $\|b\| \ll \|A\| \cdot \|x\|$ } \newpage {\samepage \clearpage $\|r^{(0)}\|$ } \newpage {\samepage \clearpage $S_5$ } \newpage {\samepage \clearpage $\|e^{(i)}\| \leq S_5 \cdot \|A^{-1}\|$ } \stepcounter{subsection} \newpage {\samepage \clearpage $x^{(i)} = M^{-1}N x^{(i-1)} + M^{-1}b \equiv Gx^{(i-1)} + c$ } \newpage {\samepage \clearpage ${\hat{r}}^{(i)} = x^{(i)} - Gx^{(i)} - c = M^{-1}(A x^{(i)}-b) = M^{-1} r^{(i)}$ } \newpage {\samepage \clearpage ${\hat{r}}^{(i)}$ } \newpage {\samepage \clearpage $M^{-1}Ax = M^{-1}b$ } \newpage {\samepage \clearpage $\| e^{(i)} \| = \|A^{-1} M {\hat{r}}^{(i)} \| \leq \|A^{-1}M\| \cdot \|{\hat{r}}^{(i)} \|$ } \newpage {\samepage \clearpage $\|A^{-1}M\|$ } \newpage {\samepage \clearpage $A^{-1}M = (M-N)^{-1} M = (I-G)^{-1}$ } \newpage {\samepage \clearpage $\|A^{-1}M\| = \|(I-G)^{-1}\| \leq 1/(1-\|G\|)$ } \newpage {\samepage \clearpage $\|r^{(i)}\|_{M^{-1/2} , 2} = (r^{(i)T} M^{-1} r^{(i)})^{1/2}$ } \newpage {\samepage \clearpage $\|r^{(i)}\|_2$ } \newpage {\samepage \clearpage $\|r^{(i)}\|_{M^{-1/2} , 2} / \|r^{(0)}\|_{M^{-1/2} , 2} \leq tol$ } \newpage {\samepage \clearpage $\|e^{(i)}\| \leq \|A^{-1} M^{1/2}\| \cdot \|r^{(i)}\|_{M^{-1/2} , 2}$ } \stepcounter{subsection} \newpage {\samepage \clearpage $e^{(i)} = A^{-1} r^{(i)}$ } \newpage {\samepage \clearpage \begin{displaymath} x^{(i)} = M^{-1}Nx^{(i-1)} + M^{-1}b = Gx^{(i-1)} + c, \end{displaymath} } \newpage {\samepage \clearpage $I-G$ } \newpage {\samepage \clearpage $\|G\|$ } \newpage {\samepage \clearpage $\| (I-G)^{-1} \| \leq 1/(1-\|G\|)$ } \newpage {\samepage \clearpage $\lambda_{\max} (A)$ } \newpage {\samepage \clearpage $\lambda_{\min} (A)$ } \newpage {\samepage \clearpage $\|A^{-1}\|_2 = \lambda^{-1}_{\min} (A)$ } \newpage {\samepage \clearpage $\|A^{-1}\|_2 = 1/ \lambda^{1/2}_{\min} (AA^T)=1/ \lambda^{1/2}_{\min} (A^TA)$ } \newpage {\samepage \clearpage $\|A^{-1}\|_{\infty}$ } \newpage {\samepage \clearpage $O(n^2)$ } \newpage {\samepage \clearpage $O(n^3)$ } \newpage {\samepage \clearpage $\| e^{(i)} \|_{\infty} \leq \| \, |A^{-1}| \cdot |r^{(i)}| \, \|_{\infty}$ } \newpage {\samepage \clearpage $\| A^{-1} \|_{\infty} \cdot \|r^{(i)}\|_{\infty}$ } \newpage {\samepage \clearpage $\| \, |A^{-1}| \cdot |r^{(i)}| \, \|_{\infty}$ } \newpage {\samepage \clearpage $R$ } \newpage {\samepage \clearpage $\| \, |A^{-1}| \cdot |r^{(i)}| \, \|_{\infty} = \| A^{-1} R \|_{\infty}$ } \newpage {\samepage \clearpage $\| A^{-1} R \|_{\infty}$ } \newpage {\samepage \clearpage $ A^{-1} R $ } \newpage {\samepage \clearpage $( A^{-1} R )^T = R^T A^{-T}$ } \newpage {\samepage \clearpage $A^{-T}$ } \stepcounter{subsection} \stepcounter{subsection} \newpage {\samepage \clearpage $\|x\|_{\infty} = \max_j |x_j|$ } \newpage {\samepage \clearpage $x_j$ } \newpage {\samepage \clearpage $\pm \infty$ } \newpage {\samepage \clearpage $\|x\|_2 = ( \sum_j |x_j|^2 )^{1/2}$ } \newpage {\samepage \clearpage $\|x\|_{\infty}$ } \newpage {\samepage \clearpage $Ax^{(i)}$ } \newpage {\samepage \clearpage $\delta r^{(i)}$ } \newpage {\samepage \clearpage $\| \delta r^{(i)} \| \leq O( \varepsilon ) (\|A\| \cdot \|x^{(i)}\| + \|b\|)$ } \newpage {\samepage \clearpage $O( \varepsilon )$ } \newpage {\samepage \clearpage $n \varepsilon$ } \newpage {\samepage \clearpage $\sqrt{n} \varepsilon$ } \newpage {\samepage \clearpage ${\em stop\_tol} \leq \varepsilon$ } \newpage {\samepage \clearpage $O( \varepsilon ) \|A^{-1}\| \cdot ( \|A\| \cdot \|x^{(i)}\| + \|b\| )$ } \newpage {\samepage \clearpage $(\delta r^{(i)})_j$ } \newpage {\samepage \clearpage $|A| \cdot |x^{(i)}| + |b|$ } \newpage {\samepage \clearpage $O (\varepsilon ) \| \, |A^{-1}| \cdot (|A| \cdot |x^{(i)}| + |b|) \|$ } \stepcounter{section} \stepcounter{subsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage $3$ } \newpage {\samepage \clearpage ${\tt val(k)}=a_{i,j}$ } \newpage {\samepage \clearpage ${\tt col\_ind(k)}=j$ } \newpage {\samepage \clearpage ${\tt row\_ptr(i)}\leq k<{\tt row\_ptr(i+1)}$ } \newpage {\samepage \clearpage ${\tt row\_ptr(n+1)} = nnz+1$ } \newpage {\samepage \clearpage $nnz$ } \newpage {\samepage \clearpage $n^2$ } \newpage {\samepage \clearpage $2nnz+n+1$ } \newpage {\samepage \clearpage \begin{equation}\label{sparseA} A = \left(\begin{array}{rrrrrr} 10 & 0 & 0 & 0 &-2 & 0 \\ 3 & 9 & 0 & 0 & 0 & 3 \\ 0 & 7 & 8 & 7 & 0 & 0 \\ 3 & 0 & 8 & 7 & 5 & 0 \\ 0 & 8 & 0 & 9 & 9 & 13 \\ 0 & 4 & 0 & 0 & 2 & -1 \end{array} \right) ~. \end{equation} } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline {\tt val} &10 &-2& 3& 9& 3& 7& 8& 7& 3 $\cdots$ 9&13& 4& 2&-1 \\ \hline {\tt col\_ind}& 1 & 5& 1& 2& 6& 2& 3& 4& 1 $\cdots$ 5& 6& 2& 5& 6 \\ \hline \end{tabular} } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|r|} \hline {\tt row\_ptr}& 1 & 3 & 6 & 9 & 13 & 17 & 20 \\ \hline \end{tabular} } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline {\tt val} &10 & 3& 3& 9& 7& 8& 4& 8& 8 $\cdots$ 9& 2& 3&13&-1 \\ \hline {\tt row\_ind}& 1 & 2& 4& 2& 3& 5& 6& 3& 4 $\cdots$ 5& 6& 2& 5& 6 \\ \hline \end{tabular} } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|r|} \hline {\tt col\_ptr}& 1 & 4 & 8 &10 & 13 & 17 & 20 \\ \hline \end{tabular} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $n_b$ } \newpage {\samepage \clearpage $nnzb$ } \newpage {\samepage \clearpage $nnz = nnzb \times n_b^2$ } \newpage {\samepage \clearpage $n_d$ } \newpage {\samepage \clearpage $ n_d = n / n_b $ } \newpage {\samepage \clearpage $1:nnzb$ } \newpage {\samepage \clearpage $1:n_b$ } \newpage {\samepage \clearpage $1,1$ } \newpage {\samepage \clearpage $1:n_d+1$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $A=(a_{i,j})$ } \newpage {\samepage \clearpage $q$ } \newpage {\samepage \clearpage $i-p\leq j\leq i+q$ } \newpage {\samepage \clearpage ${\tt p}+{\tt q}$ } \newpage {\samepage \clearpage \begin{equation}\label{sparseA2} A = \left(\begin{array}{rrrrrr} 10 & -3 & 0 & 0 & 0 & 0 \\ 3 & 9 & 6 & 0 & 0 & 0 \\ 0 & 7 & 8 & 7 & 0 & 0 \\ 0 & 0 & 8 & 7 & 5 & 0 \\ 0 & 0 & 0 & 9 & 9 & 13 \\ 0 & 0 & 0 & 0 & 2 & -1 \end{array} \right) ~. \end{equation} } \newpage {\samepage \clearpage \begin{equation}\label{eqn:diag-conversion} {\tt val(i,j)}=a_{i,i+j}. \end{equation} } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|r|r|r|r|} \hline {\tt val(:,-1)}& 0& 3& 7& 8& 9& 2\\ \hline {\tt val(:, 0)}&10& 9& 8& 7& 9&-1\\ \hline {\tt val(:,+1)}&-3& 6& 7& 5&13& 0\\ \hline \end{tabular} } \newpage {\samepage \clearpage $S = \{(i,\sigma(i));~i \in I \subseteq I_n\}$ } \newpage {\samepage \clearpage $I_n = \{1, \ldots,n\}$ } \newpage {\samepage \clearpage $\sigma$ } \newpage {\samepage \clearpage $(i,\sigma(i))$ } \newpage {\samepage \clearpage $(j,\sigma(j))$ } \newpage {\samepage \clearpage \begin{displaymath} i < j \rightarrow \sigma(i) < \sigma(j)\end{displaymath} } \newpage {\samepage \clearpage $y=Ax$ } \newpage {\samepage \clearpage $(i,\sigma_k(i))$ } \newpage {\samepage \clearpage $S_k$ } \newpage {\samepage \clearpage $x_{\sigma_k(i)}$ } \newpage {\samepage \clearpage $y_{\sigma_k(i)}$ } \newpage {\samepage \clearpage $y_i$ } \newpage {\samepage \clearpage \begin{equation}\label{sparseA3} A = \left(\begin{array}{rrrrrr} 10 & -3 & 0 & 1 & 0 & 0 \\ 0 & 9 & 6 & 0 &-2 & 0 \\ 3 & 0 & 8 & 7 & 0 & 0 \\ 0 & 6 & 0 & 7 & 5 & 4 \\ 0 & 0 & 0 & 0 & 9 & 13 \\ 0 & 0 & 0 & 0 & 5 & -1 \end{array} \right) ~, \end{equation} } \newpage {\samepage \clearpage $4$ } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|r|r|r|r|} \hline {\tt val(:,-1)}& 0& 0& 3& 6& 0& 5\\ \hline {\tt val(:, 0)}&10& 9& 8& 7& 9&-1\\ \hline {\tt val(:,+1)}& 0&-3& 6& 7& 5&13\\ \hline {\tt val(:,+2)}& 0& 1&-2& 0& 4& 0\\ \hline \end{tabular} } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{displaymath}\left(\begin{array}{rrrrrr} 10 & -3 & 0 & 1 & 0 & 0 \\ 0 & 9 & 6 & 0 &-2 & 0 \\ 3 & 0 & 8 & 7 & 0 & 0 \\ 0 & 6 & 0 & 7 & 5 & 4 \\ 0 & 0 & 0 & 0 & 9 & 13 \\ 0 & 0 & 0 & 0 & 5 & -1 \end{array} \right) \longrightarrow \left(\begin{array}{rrrr} 10 & -3 & 1 \\ 9 & 6 & -2 \\ 3 & 8 & 7 \\ 6 & 7 & 5 & 4 \\ 9 & 13 \\ 5 & -1 \end{array} \right) \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}\begin{array}{|r|r|r|r|r|r|r|} \hline {\tt val}(:,1) & 10 & 9 & 3 & 6 & 9 & 5 \\ \hline {\tt val}(:,2) & -3 & 6 & 8 & 7 & 13 & -1 \\ \hline {\tt val}(:,3) & 1 & -2 & 7 & 5 & 0 & 0 \\ \hline {\tt val}(:,4) & 0 & 0 & 0 & 4 & 0 & 0 \\ \hline \end{array}, \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}\begin{array}{|r|r|r|r|r|r|r|} \hline {\tt col\_ind}(:,1) & 1 & 2 & 1 & 2 & 5 & 5 \\ \hline {\tt col\_ind}(:,2) & 2 & 3 & 3 & 4 & 6 & 6 \\ \hline {\tt col\_ind}(:,3) & 4 & 5 & 4 & 5 & 0 & 0 \\ \hline {\tt col\_ind}(:,4) & 0 & 0 & 0 & 6 & 0 & 0 \\ \hline \end{array}. \end{displaymath} } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline {\tt jdiag} & 6 & 9& 3&10& 9 & 5; & 7& 6& 8 &-3&13&-1;&5 & -2 & 7 & 1; & 4; \\ \hline {\tt col\_ind} & 2 & 2 & 1 & 1 & 5 & 5; & 4 & 3 & 3 & 2 & 6 & 6; & 5 & 5 & 4 & 4; & 6; \\ \hline \end{tabular} } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|r|r|} \hline {\tt perm} & 4 & 2 & 3 & 1 & 5 & 6 \\ \hline \end{tabular} } \newpage {\samepage \clearpage \begin{tabular}{|r|r|r|r|r|} \hline {\tt jd\_ptr} & 1 & 7 & 13 & 17 \\ \hline \end{tabular} } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{figure}[hbt] \begin{tabular}{|ccccccccccccccccc|} \hline + & x & x & & & & & & & & & & & & & & \\ x & + & x & x & & & & & & & & & & & & & \\ x & x & + & x & & & x & & & & & & & & & & \\ & x & x & + & x & x & x & x & & & & & & & & & \\ & & & x & + & x & x & x & & & & & & & & & \\ & & x & x & x & + & x & x & & & & & & & & & \\ & & & & x & x & + & x & & & x & & x & & & & \\ & & & & x & x & x & + & x & x & x & & x & & & & \\ & & & & x & x & x & x & + & x & x & & x & & & & \\ & & & & & & & & x & + & x & x & x & & & & \\ & & & & & & x & x & x & x & + & x & x & & & & \\ & & & & & & & & & x & x & + & x & & & x & \\ & & & & & & & & & x & x & x & + & x & x & x & \\ & & & & & & & & & & & x & x & + & x & x & \\ & & & & & & & & & & & & & & + & x & x \\ & & & & & & & & & & & & x & x & x & + & x \\ & & & & & & & & & & & & & & & & + \\ \hline \end{tabular} \end{figure} } \stepcounter{subsection} \newpage {\samepage \clearpage \begin{displaymath} y=Ax\qquad\hbox{and}\qquad y=A^Tx.\end{displaymath} } \stepcounter{subsubsection} \newpage {\samepage \clearpage \begin{displaymath} y_i=\sum_j a_{i,j}x_j\end{displaymath} } \newpage {\samepage \clearpage $2n^2$ } \newpage {\samepage \clearpage $y=A^Tx$ } \newpage {\samepage \clearpage \begin{displaymath}y_i=\sum_j (A^T)_{i,j}x_j=\sum_j a_{j,i}x_j,\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} \hbox{for all $j$, do for all $i$:}\qquad y_i\leftarrow y_i+a_{j,i}x_j.\end{displaymath} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $j\rightarrow i+j$ } \newpage {\samepage \clearpage \begin{displaymath} y_i\leftarrow y_i+a_{i,j}x_j \quad\Rightarrow\quad y_i\leftarrow y_i+a_{i,i+j}x_{i+j} ~\end{displaymath} } \newpage {\samepage \clearpage $a_{i,i+j}$ } \newpage {\samepage \clearpage \begin{displaymath} 1\leq {\tt i},{\tt i+j}\leq n\end{displaymath} } \newpage {\samepage \clearpage \begin{eqnarray*} y_i&\leftarrow&y_i+a_{i+j,i}x_j \\ &=&y_i+a_{i+j,i+j-j}x_{i+j} \end{eqnarray*} } \stepcounter{subsection} \newpage {\samepage \clearpage $QMR$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $(D_A+L_A)D_A^{-1}(D_A+U_A)$ } \newpage {\samepage \clearpage ${\tt val(diag\_ptr(i))}=a_{i,i}$ } \newpage {\samepage \clearpage $a_{i,j}$ } \newpage {\samepage \clearpage $j>i$ } \newpage {\samepage \clearpage $a_{j,i}$ } \newpage {\samepage \clearpage $a_{j,j}$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $LUy=x$ } \newpage {\samepage \clearpage \begin{displaymath} Lz=x,\qquad Uy=z.\end{displaymath} } \newpage {\samepage \clearpage \begin{eqnarray*} LU&=&(D+L_A)D^{-1}(D+U_A)\\ &=&(I+L_AD^{-1})(D+U_A)\\ &=&(D+L_A)(I+D^{-1}U_A)\\ &=&(I+L_AD^{-1})D(I+D^{-1}U_A) \end{eqnarray*} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $(LU)^Ty=x$ } \newpage {\samepage \clearpage $L^T$ } \newpage {\samepage \clearpage $U^T$ } \newpage {\samepage \clearpage $L=(l_{*1},l_{*2},\ldots~)$ } \newpage {\samepage \clearpage $Ly=x$ } \newpage {\samepage \clearpage $x=l_{*1}y_1+l_{*2}y_2+\cdots$ } \newpage {\samepage \clearpage $y_1$ } \newpage {\samepage \clearpage $x\leftarrow x-l_{*1}y_1$ } \stepcounter{subsubsection} \newpage {\samepage \clearpage $ILU(k)$ } \newpage {\samepage \clearpage \begin{displaymath} \hbox{if {\tt xind(j)=i} then ${\tt x(j)}=x_i$.}\end{displaymath} } \newpage {\samepage \clearpage % latex2html id marker 7451 ${\tt This is not counting the initial zeroing of the $w$~array.} x\leftarrow {\tt \vbox{ \begin{tabbing}{ll} aaa\=bbb\=ccc\=abcdefghijklmnopqrstuvwxyzabcdefg\= \kill \> $x^{(-1)}=x^{(0)}$= initial guess; $r^{(0)}=b-Ax^{(0)};$ \\ \> $p^{(-1)}=0; \beta_{-1}=0; \alpha_{-1}=0;$\\ \> $s=L^{-1}r^{(0)}$; \\ \> $\rho_0=(s,s)$ \\ \> {\bf for} $i=0,1,2,....$ \\ \> \> $w^{(i)}=L^{-T}s;$ \> \> \\ \> \> $p^{(i)}=w^{(i)}+ \beta_{i-1}p^{(i-1)}$;\> \> \\ \> \> $q^{(i)}=Ap^{(i)};$ \> \> \\ \> \> $\gamma =(p^{(i)},q^{(i)});$ \> \> \\ \> \> $x^{(i)}=x^{(i-1)}+\alpha_{i-1}p^{(i-1)};$ \> \> \\ \> \> $\alpha_i={\rho_i}/{\gamma}$; \> \> \\ \> \> $r^{(i+1)}=r^{(i)}-\alpha_{i} q^{(i)};$ \> \> \\ \> \> $s=L^{-1}r^{(i+1)};$ \> \> \\ \> \> $\rho_{i+1}=(s,s);$ \> \> \\ \> \> {\bf if} $\|r^{(i+1)}\|$ {\em small enough} {\bf then}\> \> \\ \> \> \> $x^{(i+1)}=x^{(i)}+\alpha_ip^{(i)}$ \> \\ \> \> \> quit; \> \\ \> \> {\bf endif} \\ \> \> $\beta_i={\rho_{i+1}}/{\rho_i}$; \\ \> {\bf end}; \end{tabbing} }} x+{\tt \em or\/} y$ } \newpage {\samepage \clearpage $O({\tt lx}+{\tt ly})$ } \newpage {\samepage \clearpage $x\leftarrow x+\sum_ky^{(k)}$ } \newpage {\samepage \clearpage $y^{(i)}$ } \newpage {\samepage \clearpage $M=(D+L)(I+D^{-1} U)$ } \stepcounter{section} \newpage {\samepage \clearpage $Ap^{(i)}$ } \newpage {\samepage \clearpage $A^T p^{(i)}$ } \stepcounter{subsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage $x^{(i+1)}$ } \newpage {\samepage \clearpage $r^{(i+1)}$ } \newpage {\samepage \clearpage % latex2html id marker 7483 $\alpha_i$ } \newpage {\samepage \clearpage $\beta_{i-1}$ } \newpage {\samepage \clearpage $p^{(i)^T}Ap^{(i)}$ } \newpage {\samepage \clearpage $M=LL^T$ } \newpage {\samepage \clearpage $L^{-1}r^{(i)}$ } \newpage {\samepage \clearpage $r^{(i)^T}M^{-1}r^{(i)}$ } \newpage {\samepage \clearpage $s^Ts$ } \newpage {\samepage \clearpage $s=L^{-1}r^{(i)}$ } \newpage {\samepage \clearpage $L^{-T}s$ } \newpage {\samepage \clearpage \begin{figure}[ht] \begin{center} \leavevmode \framebox[4.0in] \label{fig:rearrangedcg} \end{center} \end{figure} } \newpage {\samepage \clearpage $\gamma$ } \newpage {\samepage \clearpage $\rho_{i+1}$ } \newpage {\samepage \clearpage $q^{(i)}$ } \newpage {\samepage \clearpage $LDL^T$ } \stepcounter{subsubsection} \stepcounter{subsection} \stepcounter{subsection} \newpage {\samepage \clearpage $Ap_i$ } \newpage {\samepage \clearpage $p_i$ } \stepcounter{subsection} \stepcounter{paragraph} \stepcounter{paragraph} \stepcounter{paragraph} \stepcounter{subsection} \newpage {\samepage \clearpage $D-L$ } \newpage {\samepage \clearpage $i+d$ } \stepcounter{subsection} \newpage {\samepage \clearpage $M^{-1}Av^{(j)}$ } \newpage {\samepage \clearpage $v^{(1)}$ } \newpage {\samepage \clearpage $v^{(2)}$ } \newpage {\samepage \clearpage $v^{(j)}$ } \newpage {\samepage \clearpage $Av^{(1)}$ } \newpage {\samepage \clearpage $A^mv^{(1)}$ } \stepcounter{chapter} \stepcounter{section} \newpage {\samepage \clearpage $n \times k$ } \newpage {\samepage \clearpage $R^{(k)}$ } \newpage {\samepage \clearpage \begin{displaymath} R_k = [ r^{(0)}, ~ r^{(1)}, ~ \ldots,~ r^{(k-1)} ] , \end{displaymath} } \newpage {\samepage \clearpage $k \times k$ } \newpage {\samepage \clearpage $B_k$ } \newpage {\samepage \clearpage \begin{displaymath} B_k = \left [ \begin{array}{ccccc} 1 & - \beta_1 & & \cdots & 0 \\ & 1 & - \beta_2 & &\vdots \\ & \ddots & \ddots & \ddots & \\ \vdots & & \ddots & \ddots & - \beta_{k-1} \\ 0 & \cdots & & & 1 \\ \end{array} \right ] , \end{displaymath} } \newpage {\samepage \clearpage $\{r^{(k)}\}$ } \newpage {\samepage \clearpage $\{\beta_k\}$ } \newpage {\samepage \clearpage \begin{displaymath} p^{(j)} = r^{(j-1)} + \beta_{j-1} p^{(j-1)}, ~ j = 2,~3,~ \ldots,~ k~, \end{displaymath} } \newpage {\samepage \clearpage $p^{(1)}=r^{(0)}$ } \newpage {\samepage \clearpage $R_k = P_k B_k$ } \newpage {\samepage \clearpage \begin{displaymath} P_k = [ p^{(1)}, ~ p^{(2)}, ~ \ldots,~ p^{(k)} ] . \end{displaymath} } \newpage {\samepage \clearpage $\{p^{(j)}\}$ } \newpage {\samepage \clearpage \begin{displaymath} \hat{T}_k = R_k^T A R_k = B_k^T \hat{\Lambda}_k B_k \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} \hat{\Lambda}_k = \left [ \begin{array}{ccccc} p^{(1)^T}Ap^{(1)}& 0 & & \cdots & 0 \\ 0 &p^{(2)^T}Ap^{(2)} & & &\vdots \\ & \ddots & \ddots & \ddots & \\ \vdots & & \ddots & \ddots & 0 \\ 0 & \cdots & & 0 & p^{(k)^T}Ap^{(k)} \\ \end{array} \right ] . \end{displaymath} } \newpage {\samepage \clearpage $p^{(1)},~p^{(2)},~\ldots,~p^{(j)}$ } \newpage {\samepage \clearpage $r^{(0)},~r^{(1)},~\ldots,~r^{(j-1)}$ } \newpage {\samepage \clearpage $\{r^{(j)}\}$ } \newpage {\samepage \clearpage $Q_k = R_k\Delta^{-1}$ } \newpage {\samepage \clearpage ${\rm span}\{b,~ Ab,~ \ldots,~ A^{k-1}b\}$ } \newpage {\samepage \clearpage $\Delta$ } \newpage {\samepage \clearpage $Q_k$ } \newpage {\samepage \clearpage \begin{equation} T_k = \Delta^{-1} B_k^T \hat\Lambda_k B_k \Delta^{-1} ~. \label{proj} \end{equation} } \newpage {\samepage \clearpage $T_k$ } \stepcounter{section} \newpage {\samepage \clearpage $n_b-1$ } \stepcounter{section} \newpage {\samepage \clearpage \begin{displaymath} M^{-1} A x = M^{-1}f \end{displaymath} } \newpage {\samepage \clearpage $Ax=f$ } \newpage {\samepage \clearpage $Mz=r$ } \newpage {\samepage \clearpage $5$ } \newpage {\samepage \clearpage \begin{equation} \label{redblk} Ax= \left[ \begin{array}{cc} D_R & C \\ C^T & D_B \end{array} \right] \left[ \begin{array}{c} x_R \\ x_B \end{array} \right] = \left[ \begin{array}{c} f_R \\ f_B \end{array} \right]~, \end{equation} } \newpage {\samepage \clearpage $D_R$ } \newpage {\samepage \clearpage $D_B$ } \newpage {\samepage \clearpage $C$ } \newpage {\samepage \clearpage \begin{displaymath} \left[ \begin{array}{cc} I & O \\ -C^TD_R^{-1} & I \end{array} \right] \left[ \begin{array}{cc} D_R & C \\ C^T & D_B \end{array} \right] \left[ \begin{array}{c} x_R \\ x_B \end{array} \right] = \left[ \begin{array}{cc} I & O \\ -C^TD_R^{-1} & I \end{array} \right] \left[ \begin{array}{c} f_R \\ f_B \end{array} \right] \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} \left[ \begin{array}{cc} D_R & C \\ O & D_B-C^T{D_R}^{-1}C\end{array} \right] \left[ \begin{array}{c} x_R \\ x_B \end{array} \right] = \left[ \begin{array}{c} f_R \\ f_B -C^T{D_R}^{-1}f_R \end{array} \right] . \end{displaymath} } \newpage {\samepage \clearpage ${D_B}^{-1/2}$ } \newpage {\samepage \clearpage \begin{equation} \label{rs} (I-H^TH)y =g ~, \end{equation} } \newpage {\samepage \clearpage $H = D_R^{-1/2}CD_B^{-1/2}$ } \newpage {\samepage \clearpage $y=D_B^{1/2}x_B$ } \newpage {\samepage \clearpage $g = D_B^{-1/2}(f_B-C^TD_R^{-1}f_R)$ } \newpage {\samepage \clearpage $n^2/2$ } \newpage {\samepage \clearpage $(n^2-1)/2$ } \newpage {\samepage \clearpage $n \ge 250$ } \stepcounter{section} \newpage {\samepage \clearpage \begin{eqnarray} -\nabla \cdot (a(x,y) \nabla u) = f(x,y) \label{prob} \end{eqnarray} } \newpage {\samepage \clearpage $a(x,y)$ } \newpage {\samepage \clearpage $\Omega$ } \newpage {\samepage \clearpage $u$ } \newpage {\samepage \clearpage $T_H$ } \newpage {\samepage \clearpage $\Omega_i, i=1,...,p$ } \newpage {\samepage \clearpage $n_H$ } \newpage {\samepage \clearpage $\Omega_i$ } \newpage {\samepage \clearpage $T_h$ } \newpage {\samepage \clearpage $H, h$ } \newpage {\samepage \clearpage $Au=f$ } \newpage {\samepage \clearpage $S_Bu_B=g_B$ } \newpage {\samepage \clearpage $Av$ } \newpage {\samepage \clearpage $Sw$ } \newpage {\samepage \clearpage $v$ } \newpage {\samepage \clearpage $K^{-1}v$ } \stepcounter{subsection} \newpage {\samepage \clearpage $\omip$ } \newpage {\samepage \clearpage $n'_i$ } \newpage {\samepage \clearpage $T'_i \subset T_h$ } \newpage {\samepage \clearpage $A'_i, A_H$ } \newpage {\samepage \clearpage $T'_i$ } \newpage {\samepage \clearpage $R^T_i$ } \newpage {\samepage \clearpage $R_i$ } \newpage {\samepage \clearpage $R^T_H$ } \newpage {\samepage \clearpage $R_H$ } \newpage {\samepage \clearpage $K_{as}$ } \newpage {\samepage \clearpage \begin{displaymath}K_{as}^{-1}v = R_H^T A_H^{-1} R_H v+ \sum_{i=1}^p R_i^T {A'}_i^{-1} R_i v.\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$p\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A'_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$ R_i^T {A'}_i^{-1} R_i v \end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$v_i=R_i v\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$w_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A'_i w_i=v_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$y_i=R^T_i w_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$K_{as}^{-1}A\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$h\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\Omega_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\omip\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\delta/H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\delta\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$ \partial \omip\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$ \partial \Omega_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$h \rightarrow 0\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$O(1/H^2)\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$K_{as}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\Omega\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$u\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$I_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$n'_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$n'_i \times n'_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R^T_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$n \times n'_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$u_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$T'_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$(R^T_i u_i)_j=(u_i)_j\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$j \in I_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R_i u\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R^T_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$n \times n_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$T_h\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$T_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R_H, R^T_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R^T_i, R_i, R^T_H, R_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R_i, A'_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_H, R_H\end{displaymath} } \stepcounter{subsection} \newpage {\samepage \clearpage $\bigcup_{i} \partial \omip$ } \newpage {\samepage \clearpage $u\equiv (u_I,u_B)^T$ } \newpage {\samepage \clearpage $f\equiv (f_I, f_B)^T$ } \newpage {\samepage \clearpage \begin{eqnarray}\left( \begin{array}{cc} A_I & A_{IB} \\ A^T_{IB} & A_B \end{array} \right) \left(\begin{array}{c} u_I \\ u_B \end{array} \right) = \left(\begin{array}{c} f_I \\ f_B \end{array} \right). \label{block-eqn1} \end{eqnarray} } \newpage {\samepage \clearpage $A_{I} = blockdiagonal(A_{i})$ } \newpage {\samepage \clearpage $A_i$ } \newpage {\samepage \clearpage \begin{eqnarray}\left(\begin{array}{cc} I & 0 \\ A^T_{IB}A_I^{-1} & I \end{array} \right) \left(\begin{array}{cc} A_I & A_{IB} \\ 0 & S_B \end{array} \right) \left(\begin{array}{c} u_I \\ u_B \end{array} \right) = \left(\begin{array}{c} f_I \\ f_B \end{array} \right), \label{block-eqn2} \end{eqnarray} } \newpage {\samepage \clearpage \begin{displaymath}S_B \equiv A_B - A_{IB}^T A_I^{-1} A_{IB}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$u_I\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$u_B\end{displaymath} } \newpage {\samepage \clearpage \begin{eqnarray}S_B u_B = g_B \equiv f_B-A_{IB}A_I^{-1}f_I. \label{SB-eqn} \end{eqnarray} } \newpage {\samepage \clearpage \begin{displaymath}$S_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$O(h^{-1})\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$O(h^{-2})\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$v_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$S_B v_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_Bv_B - A_{IB}^T (A_I^{-1} (A_{IB}v_B))\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_{I}^{-1}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_i^{-1}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$g_B\end{displaymath} } \newpage {\samepage \clearpage \begin{eqnarray}B = E \cup V_H \label{BPS-part} \end{eqnarray} } \newpage {\samepage \clearpage \begin{displaymath}$V_H=\bigcup_k V_k\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$V_k\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$E=\bigcup_i E_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$E_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$V_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R_{E_i}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$n_{E_i} \times n\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$n_{E_i}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$(R_{E_i} u_B)_j = (u_B)_j\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$j \in E_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$S\end{displaymath} } \newpage {\samepage \clearpage \begin{eqnarray}S_B=\left(\begin{array}{cc} S_E & S_{EV} \\ S^T_{EV} & S_V \end{array} \right). \label{SB-block} \end{eqnarray} } \newpage {\samepage \clearpage \begin{displaymath}$S_E\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$S_{E_i}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$S_{E_i}^{-1}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}% latex2html id marker 8035 M_{E_i} = \alpha_{E_i} K^{1/2}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$K\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$n_{E_i} \times n_{E_i}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$2\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$-1\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}% latex2html id marker 8045 $\alpha_{E_i}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$a(x,y)\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$M_{E_i}\end{displaymath} } \newpage {\samepage \clearpage \begin{eqnarray}K_{BPS}^{-1} v_B = R^T_H A^{-1}_H R_H v_B + \sum_{E_i} R^T_{E_i} M_{E_i}^{-1} R_{E_i} v_B. \label{BPS-def1} \end{eqnarray} } \newpage {\samepage \clearpage \begin{displaymath}$K_{BPS}^{-1}S_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$O(1+\log^2(H/h))\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\log^2(H/h)\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$K_{BPS}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$X=\bigcup_k X_k\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$X_k\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$X\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$E\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$S_{X_k}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$R_{X_k}, R^T_{X_k}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$K^{1/2}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$M_{X_k}\end{displaymath} } \newpage {\samepage \clearpage \begin{eqnarray} K_{VS}^{-1} v_B &=& R^T_H A^{-1}_H R_H v_B + \sum_{E_i} R^T_{E_i} M_{E_i}^{-1} R_{E_i} v_B \nonumber \\ & & \mbox{} + \sum_{X_k} R^T_{X_k} M_{X_k}^{-1} R_{X_k} v_B. \label{VS-def1} \end{eqnarray} } \newpage {\samepage \clearpage \begin{displaymath}$K_{VS}^{-1}S_B\end{displaymath} } \stepcounter{subsection} \stepcounter{subsubsection} \stepcounter{subsubsection} \newpage {\samepage \clearpage ${A'}_i^{-1}, A_i^{-1}$ } \newpage {\samepage \clearpage $A_H^{-1}$ } \newpage {\samepage \clearpage $K_{as}, K_{BPS}, K_{VS}$ } \newpage {\samepage \clearpage ${\tilde{A'}}_i^{-1}, \tilde{A}_i^{-1}$ } \newpage {\samepage \clearpage $\tilde{A}_H^{-1}$ } \newpage {\samepage \clearpage \begin{displaymath}\tilde{K}_{as}^{-1}v = R_H^T \tilde{A}_H^{-1} R_H v+ \sum_{i=1}^p R_i^T {\tilde{A'}}_i^{-1} R_i v.\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_H^{-1}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{A}_H^{-1}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$K_{VS}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{K}_{BPS}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{K}_{VS}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{A}_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_I, S_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{A}_I, \tilde{S}_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{S}_B\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{A}_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{A}_H^{-1}A_H\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$\tilde{A}_i^{-1}A_i\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath}$A_{IB}\end{displaymath} } \stepcounter{subsubsection} \newpage {\samepage \clearpage $H$ } \stepcounter{subsubsection} \stepcounter{section} \newpage {\samepage \clearpage $2\times2$ } \newpage {\samepage \clearpage \begin{displaymath} A^{(i)}=\pmatrix{A^{(i)}_{1,1}&A^{(i)}_{1,2}\cr A^{(i)}_{2,1}&A^{(i)}_{2,2}}\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} A^{(i+1)}\approx S^{(i)}=A^{(i)}_{2,2}- A^{(i)}_{2,1}A^{(i)^{-1}}_{1,1}A^{(i)}_{1,2}.\end{displaymath} } \stepcounter{section} \newpage {\samepage \clearpage \begin{displaymath} A^T=[A_1,\ldots,A_m]\end{displaymath} } \newpage {\samepage \clearpage \begin{displaymath} P_ix=A_i(A^T_iA_i)^{-1} A^T_ix.\end{displaymath} } \appendix \stepcounter{chapter} \newpage {\samepage \clearpage \begin{tabular}{l l} shar filename & contents \\ \hline sctemplates.shar & Single precision C routines\\ dctemplates.shar & Double precision C routines\\ sftemplates.shar & Single Precision Fortran 77 routines\\ dftemplates.shar & Double Precision Fortran 77 routines\\ mltemplates.shar & MATLAB routines\\ cpptemplates.shar & C++ template routines\\ \end{tabular} } \newpage {\samepage \clearpage \begin{tabular}{l l} shar filename & contents \\ \hline sctemplates.shar & Single precision C routines\\ dctemplates.shar & Double precision C routines\\ sftempaltes.shar & Single Precision Fortran 77 routines\\ dftemplates.shar & Double Precision Fortran 77 routines\\ mltemplates.shar & MATLAB kernels\\ \end{tabular} } \stepcounter{chapter} \newpage {\samepage \clearpage $Tx = b$ } \newpage {\samepage \clearpage $a_{i,j} = $ } \newpage {\samepage \clearpage % latex2html id marker 8227 $\alpha$ } \newpage {\samepage \clearpage % latex2html id marker 8233 $\alpha$ } \newpage {\samepage \clearpage $Ax + b$ } \newpage {\samepage \clearpage $b - A\hat{x}$ } \newpage {\samepage \clearpage $Ax$ } \stepcounter{chapter} \newpage {\samepage \clearpage $a_{i,j}=0$ } \newpage {\samepage \clearpage $ji+q$ } \newpage {\samepage \clearpage $A=LL^T$ } \newpage {\samepage \clearpage $\{x^TAx:x^Tx=1\}$ } \newpage {\samepage \clearpage $[\lambda_{\min}(A),\lambda_{\max}(A)]$ } \newpage {\samepage \clearpage $A\not=LU$ } \newpage {\samepage \clearpage $Q$ } \newpage {\samepage \clearpage $A=LQ$ } \newpage {\samepage \clearpage $A=LU$ } \newpage {\samepage \clearpage $a_{i,i}>\sum_{j\not=i}|a_{i,j}|$ } \newpage {\samepage \clearpage $\min_i\{a_{i,i}-\sum_{j\not=i}|a_{i,j}|\}$ } \newpage {\samepage \clearpage $A A^T y = b$ } \newpage {\samepage \clearpage $A^H$ } \newpage {\samepage \clearpage $f:R^n\rightarrow R$ } \newpage {\samepage \clearpage $f(x)\geq0$ } \newpage {\samepage \clearpage $f(x)=0$ } \newpage {\samepage \clearpage $x=0$ } \newpage {\samepage \clearpage % latex2html id marker 8401 $f(\alpha x)=|\alpha|f(x)$ } \newpage {\samepage \clearpage % latex2html id marker 8403 $\alpha$ } \newpage {\samepage \clearpage $f(x+y)\leq f(x)+f(y)$ } \newpage {\samepage \clearpage $\|\cdot\|$ } \newpage {\samepage \clearpage \begin{displaymath} \|Ax\|\leq \|A\|\,\|x\|. \end{displaymath} } \newpage {\samepage \clearpage $i+j$ } \newpage {\samepage \clearpage $Ay-b$ } \newpage {\samepage \clearpage \begin{displaymath} \|A\|_2 \cdot\|A^{-1}\|_2=\frac{\lambda^{1/2}_{\max}(A^TA)} {\lambda^{1/2}_{\min}(A^TA)}, \end{displaymath} } \newpage {\samepage \clearpage $j 0$ } \newpage {\samepage \clearpage $A^{-1} > 0$ } \newpage {\samepage \clearpage $\ell$ } \stepcounter{chapter} \end{document} .