cpotrf2.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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NAME

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 real symmetric
 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 symmetric 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 minor of order i is not
                positive definite, and the factorization could not be
                completed.


 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

June 2016

Definition at line 108 of file cpotrf2.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
Function/Subroutine Documentation
recursive subroutine cpotrf2 (character UPLO, integer N, complex, dimension( lda, * ) A, integer LDA, integer INFO)
Author
LinuxReviews : manual page archive : man3