dpotrs(3P) Sun Performance Library dpotrs(3P)NAMEdpotrs - 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 DPOTRF
SYNOPSIS
SUBROUTINE DPOTRS(UPLO, N, NRHS, A, LDA, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER N, NRHS, LDA, LDB, INFO
DOUBLE PRECISION A(LDA,*), B(LDB,*)
SUBROUTINE DPOTRS_64(UPLO, N, NRHS, A, LDA, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER*8 N, NRHS, LDA, LDB, INFO
DOUBLE PRECISION A(LDA,*), B(LDB,*)
F95 INTERFACE
SUBROUTINE POTRS(UPLO, [N], [NRHS], A, [LDA], B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, NRHS, LDA, LDB, INFO
REAL(8), DIMENSION(:,:) :: A, B
SUBROUTINE POTRS_64(UPLO, [N], [NRHS], A, [LDA], B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, NRHS, LDA, LDB, INFO
REAL(8), DIMENSION(:,:) :: A, B
C INTERFACE
#include <sunperf.h>
void dpotrs(char uplo, int n, int nrhs, double *a, int lda, double *b,
int ldb, int *info);
void dpotrs_64(char uplo, long n, long nrhs, double *a, long lda, dou‐
ble *b, long ldb, long *info);
PURPOSEdpotrs 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 DPOTRF.
ARGUMENTS
UPLO (input)
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
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 triangular factor U or L from the Cholesky factorization
A = U**T*U or A = L*L**T, as computed by DPOTRF.
LDA (input)
The leading dimension of the array A. LDA >= max(1,N).
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 dpotrs(3P)
