dsptrs(3P) Sun Performance Library dsptrs(3P)NAMEdsptrs - solve a system of linear equations A*X = B with a real symmet‐
ric matrix A stored in packed format using the factorization A =
U*D*U**T or A = L*D*L**T computed by DSPTRF
SYNOPSIS
SUBROUTINE DSPTRS(UPLO, N, NRHS, AP, IPIVOT, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER N, NRHS, LDB, INFO
INTEGER IPIVOT(*)
DOUBLE PRECISION AP(*), B(LDB,*)
SUBROUTINE DSPTRS_64(UPLO, N, NRHS, AP, IPIVOT, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER*8 N, NRHS, LDB, INFO
INTEGER*8 IPIVOT(*)
DOUBLE PRECISION AP(*), B(LDB,*)
F95 INTERFACE
SUBROUTINE SPTRS(UPLO, [N], [NRHS], AP, IPIVOT, B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, NRHS, LDB, INFO
INTEGER, DIMENSION(:) :: IPIVOT
REAL(8), DIMENSION(:) :: AP
REAL(8), DIMENSION(:,:) :: B
SUBROUTINE SPTRS_64(UPLO, [N], [NRHS], AP, IPIVOT, B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, NRHS, LDB, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
REAL(8), DIMENSION(:) :: AP
REAL(8), DIMENSION(:,:) :: B
C INTERFACE
#include <sunperf.h>
void dsptrs(char uplo, int n, int nrhs, double *ap, int *ipivot, double
*b, int ldb, int *info);
void dsptrs_64(char uplo, long n, long nrhs, double *ap, long *ipivot,
double *b, long ldb, long *info);
PURPOSEdsptrs solves a system of linear equations A*X = B with a real symmet‐
ric matrix A stored in packed format using the factorization A =
U*D*U**T or A = L*D*L**T computed by DSPTRF.
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.
AP (input)
Double precision array, dimension (N*(N+1)/2) The block diag‐
onal matrix D and the multipliers used to obtain the factor U
or L as computed by DSPTRF, stored as a packed triangular
matrix.
IPIVOT (input)
Integer array, dimension (N) Details of the interchanges and
the block structure of D as determined by DSPTRF.
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)
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 dsptrs(3P)