dsytrs(3P) Sun Performance Library dsytrs(3P)NAMEdsytrs - solve a system of linear equations A*X = B with a real symmet‐
ric matrix A using the factorization A = U*D*U**T or A = L*D*L**T com‐
puted by DSYTRF
SYNOPSIS
SUBROUTINE DSYTRS(UPLO, N, NRHS, A, LDA, IPIVOT, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER N, NRHS, LDA, LDB, INFO
INTEGER IPIVOT(*)
DOUBLE PRECISION A(LDA,*), B(LDB,*)
SUBROUTINE DSYTRS_64(UPLO, N, NRHS, A, LDA, IPIVOT, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER*8 N, NRHS, LDA, LDB, INFO
INTEGER*8 IPIVOT(*)
DOUBLE PRECISION A(LDA,*), B(LDB,*)
F95 INTERFACE
SUBROUTINE SYTRS(UPLO, N, NRHS, A, [LDA], IPIVOT, B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, NRHS, LDA, LDB, INFO
INTEGER, DIMENSION(:) :: IPIVOT
REAL(8), DIMENSION(:,:) :: A, B
SUBROUTINE SYTRS_64(UPLO, N, NRHS, A, [LDA], IPIVOT, B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, NRHS, LDA, LDB, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
REAL(8), DIMENSION(:,:) :: A, B
C INTERFACE
#include <sunperf.h>
void dsytrs(char uplo, int n, int nrhs, double *a, int lda, int
*ipivot, double *b, int ldb, int *info);
void dsytrs_64(char uplo, long n, long nrhs, double *a, long lda, long
*ipivot, double *b, long ldb, long *info);
PURPOSEdsytrs solves a system of linear equations A*X = B with a real symmet‐
ric matrix A using the factorization A = U*D*U**T or A = L*D*L**T com‐
puted by DSYTRF.
ARGUMENTS
UPLO (input)
Specifies whether the details of the factorization are stored
as an upper or lower triangular matrix. = 'U': Upper trian‐
gular, form is A = U*D*U**T;
= 'L': Lower triangular, form is A = L*D*L**T.
N (input) The order of the matrix A. N >= 0.
NRHS (input)
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.
A (input) The block diagonal matrix D and the multipliers used to
obtain the factor U or L as computed by DSYTRF.
LDA (input)
The leading dimension of the array A. LDA >= max(1,N).
IPIVOT (input)
Details of the interchanges and the block structure of D as
determined by DSYTRF.
B (input/output)
On entry, the right hand side matrix B. On exit, the solu‐
tion matrix X.
LDB (input)
The leading dimension of the array B. LDB >= max(1,N).
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
6 Mar 2009 dsytrs(3P)
