spotrs (l) - Linux Manuals

spotrs: solves a system of linear equations A*X = B with a symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF

NAME

SPOTRS - solves a system of linear equations A*X = B with a symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF

SYNOPSIS

SUBROUTINE SPOTRS(

UPLO, N, NRHS, A, LDA, B, LDB, INFO )

    

CHARACTER UPLO

    

INTEGER INFO, LDA, LDB, N, NRHS

    

REAL A( LDA, * ), B( LDB, * )

PURPOSE

SPOTRS solves a system of linear equations A*X = B with a symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF.

ARGUMENTS

UPLO (input) CHARACTER*1

= aqUaq: Upper triangle of A is stored;
= aqLaq: Lower triangle of A is stored.

N (input) INTEGER

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

NRHS (input) INTEGER

The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.

A (input) REAL array, dimension (LDA,N)

The triangular factor U or L from the Cholesky factorization A = U**T*U or A = L*L**T, as computed by SPOTRF.

LDA (input) INTEGER

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

B (input/output) REAL array, dimension (LDB,NRHS)

On entry, the right hand side matrix B. On exit, the solution matrix X.

LDB (input) INTEGER

The leading dimension of the array B. LDB >= max(1,N).

INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value