NAME

dsytrs - solve a system of linear equations A∗X = B with a real symmetric matrix A using the factorization A = U∗D∗U∗∗T or A = L∗D∗L∗∗T computed by DSYTRF

SYNOPSIS

SUBROUTINE DSYTRS(
UPLO, N, NRHS, A, LDA, IPIV, B, LDB, INFO )

CHARACTER UPLO

INTEGER INFO, LDA, LDB, N, NRHS

INTEGER IPIV( ∗ )

DOUBLE PRECISION A( LDA, ∗ ), B( LDB, ∗ )

PURPOSE

DSYTRS solves a system of linear equations A∗X = B with a real symmetric matrix A using the factorization A = U∗D∗U∗∗T or A = L∗D∗L∗∗T computed by DSYTRF. 
 

ARGUMENTS

UPLO    (input) CHARACTER∗1
Specifies whether the details of the factorization are stored as an upper or lower triangular matrix. = ’U’:  Upper triangular, form is A = U∗D∗U∗∗T;
= ’L’:  Lower triangular, form is A = L∗D∗L∗∗T.

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) DOUBLE PRECISION array, dimension (LDA,N)
The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by DSYTRF.

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

IPIV    (input) INTEGER array, dimension (N)
Details of the interchanges and the block structure of D as determined by DSYTRF.

B       (input/output) DOUBLE PRECISION 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

SunSoft, Inc.  —  Last change: 27 Jun 1995