!-----------------------------------------------------------------
!
! Purpose
! =======
!
! LA_POTRF computes the Cholesky factorization of a real symmetric or
! complex Hermitian positive definite matrix A.
!
! The factorization has the form
!    A = U**H * U,  if UPLO = 'U', or
!    A = L * L**H,  if UPLO = 'L',
! where U is an upper triangular matrix and L is lower triangular.
!
! This is the block version of the algorithm, calling Level 3 BLAS.
!
! LA_POTRF optionally estimates the reciprocal of the condition number
! (in the 1-norm) of a real symmetric or complex Hermitian positive 
! definite matrix A.
! An estimate is obtained for norm(inv(A)), and the reciprocal of the
! condition number is computed as RCOND = 1 / (norm(A) * norm(inv(A))).
!
! =======
!
!    SUBROUTINE LA_POTRF( A, UPLO, RCOND, NORM, INFO )
!       <type>(<wp>), INTENT(INOUT) :: A(:,:)
!       CHARACTER(LEN=1), INTENT(IN), OPTIONAL :: UPLO
!       REAL(<wp>), INTENT(OUT), OPTIONAL :: RCOND
!       CHARACTER(LEN=1), INTENT(IN), OPTIONAL :: NORM
!       INTEGER, INTENT(OUT), OPTIONAL :: INFO
!    where
!       <type> ::= REAL | COMPLEX
!       <wp>   ::= KIND(1.0) | KIND(1.0D0)
!
! Defaults
! ========
!
! 1. If UPLO is not present then UPLO = 'U' is assumed.
!
! Arguments
! =========
!
! A       (input/output) either REAL or COMPLEX square array, 
!         shape (:,:), size(A,1) == size(A,2) >= 0.
!         On entry, the symmetric (Hermitian) matrix A.  
!            If UPLO = 'U', the upper triangular part of A contains
!               the upper triangular part of the matrix A, and the 
!               strictly lower triangular part of A is not referenced.
!            If UPLO = 'L', the lower triangular part of A contains
!               the lower triangular part of the matrix A, and the
!               strictly upper triangular part of A is not referenced.
!         On exit, if INFO = 0, the factor U or L from the Cholesky
!            factorization A = U**H*U or A = L*L**H.
!
! UPLO    Optional, (input) CHARACTER*1
!         If UPLO is present then:
!            = 'U':  Upper triangle of A is stored;
!            = 'L':  Lower triangle of A is stored.
!         otherwise UPLO = 'U' is assumed.
!
! RCOND   Optional (output) REAL
!         The reciprocal of the condition number of the matrix A 
!         computed as RCOND = 1/(norm(A) * norm(inv(A))).
! NORM    Optional (input) CHARACTER*1
!         Specifies whether the 1-norm condition number or the
!         infinity-norm condition number is required:
!           If NORM is present then:
!              = '1', 'O' or 'o': 1-norm;
!              = 'I' or 'i': infinity-norm.
!           otherwise NORM = '1' is used.
!
! INFO    Optional, (output) INTEGER
!         If INFO is present:
!            = 0: successful exit
!            < 0: if INFO = -i, the i-th argument had an illegal value
!            > 0: if INFO = i, the leading minor of order i is not
!               positive definite, and the factorization could not be
!               completed.
!         If INFO is not present and an error occurs, then the program
!            is terminated with an error message.
!
! --------------------------------------

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