NAME

spotrs - solve 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, ∗ )

#include <sunperf.h>

void spotrs(char uplo, int n, int nrhs, float ∗sa, int lda, float ∗sb, int ldb, int ∗info) ;

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
= ’U’:  Upper triangle of A is stored;
= ’L’:  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

SunOS 5.0  —  Last change: 10 Dec 1998