SRC/cpotrf2.f(3)           Library Functions Manual           SRC/cpotrf2.f(3)

NAME
       SRC/cpotrf2.f

SYNOPSIS
   Functions/Subroutines
       recursive subroutine cpotrf2 (uplo, n, a, lda, info)
           CPOTRF2

Function/Subroutine Documentation
   recursive subroutine cpotrf2 (character uplo, integer n, complex,
       dimension( lda, * ) a, integer lda, integer info)
       CPOTRF2

       Purpose:


            CPOTRF2 computes the Cholesky factorization of a Hermitian
            positive definite matrix A using the recursive algorithm.

            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 recursive version of the algorithm. It divides
            the matrix into four submatrices:

                   [  A11 | A12  ]  where A11 is n1 by n1 and A22 is n2 by n2
               A = [ -----|----- ]  with n1 = n/2
                   [  A21 | A22  ]       n2 = n-n1

            The subroutine calls itself to factor A11. Update and scale A21
            or A12, update A22 then calls itself to factor A22.

       Parameters
           UPLO

                     UPLO is CHARACTER*1
                     = 'U':  Upper triangle of A is stored;
                     = 'L':  Lower triangle of A is stored.

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           A

                     A is COMPLEX array, dimension (LDA,N)
                     On entry, the Hermitian matrix A.  If UPLO = 'U', the leading
                     N-by-N 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
                     leading N-by-N 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.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(1,N).

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument had an illegal value
                     > 0:  if INFO = i, the leading principal minor of order i
                           is not positive, and the factorization could not be
                           completed.

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 105 of file cpotrf2.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                SRC/cpotrf2.f(3)