spotf2.f man page

spotf2.f —

Synopsis

Functions/Subroutines

subroutine spotf2 (UPLO, N, A, LDA, INFO)
SPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm).

Function/Subroutine Documentation

subroutine spotf2 (characterUPLO, integerN, real, dimension( lda, * )A, integerLDA, integerINFO)

SPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm).

Purpose:

SPOTF2 computes the Cholesky factorization of a real symmetric
positive definite matrix A.

The factorization has the form
   A = U**T * U ,  if UPLO = 'U', or
   A = L  * L**T,  if UPLO = 'L',
where U is an upper triangular matrix and L is lower triangular.

This is the unblocked version of the algorithm, calling Level 2 BLAS.

Parameters:

UPLO

UPLO is CHARACTER*1
Specifies whether the upper or lower triangular part of the
symmetric matrix A is stored.
= 'U':  Upper triangular
= 'L':  Lower triangular

N

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

A

A is REAL 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**T *U  or A = L*L**T.

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 = -k, the k-th argument had an illegal value
> 0: if INFO = k, the leading minor of order k 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:

September 2012

Definition at line 110 of file spotf2.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

spotf2(3) is an alias of spotf2.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK