cporfs - improve the computed solution to a system of linear equations when the coefficient matrix is Hermitian positive definite,
SUBROUTINE CPORFS( UPLO, N, NRHS, A, LDA, AF, LDAF, B, LDB, X, LDX, * FERR, BERR, WORK, WORK2, INFO) CHARACTER * 1 UPLO COMPLEX A(LDA,*), AF(LDAF,*), B(LDB,*), X(LDX,*), WORK(*) INTEGER N, NRHS, LDA, LDAF, LDB, LDX, INFO REAL FERR(*), BERR(*), WORK2(*)
SUBROUTINE CPORFS_64( UPLO, N, NRHS, A, LDA, AF, LDAF, B, LDB, X, * LDX, FERR, BERR, WORK, WORK2, INFO) CHARACTER * 1 UPLO COMPLEX A(LDA,*), AF(LDAF,*), B(LDB,*), X(LDX,*), WORK(*) INTEGER*8 N, NRHS, LDA, LDAF, LDB, LDX, INFO REAL FERR(*), BERR(*), WORK2(*)
SUBROUTINE PORFS( UPLO, [N], [NRHS], A, [LDA], AF, [LDAF], B, [LDB], * X, [LDX], FERR, BERR, [WORK], [WORK2], [INFO]) CHARACTER(LEN=1) :: UPLO COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A, AF, B, X INTEGER :: N, NRHS, LDA, LDAF, LDB, LDX, INFO REAL, DIMENSION(:) :: FERR, BERR, WORK2
SUBROUTINE PORFS_64( UPLO, [N], [NRHS], A, [LDA], AF, [LDAF], B, * [LDB], X, [LDX], FERR, BERR, [WORK], [WORK2], [INFO]) CHARACTER(LEN=1) :: UPLO COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A, AF, B, X INTEGER(8) :: N, NRHS, LDA, LDAF, LDB, LDX, INFO REAL, DIMENSION(:) :: FERR, BERR, WORK2
#include <sunperf.h>
void cporfs(char uplo, int n, int nrhs, complex *a, int lda, complex *af, int ldaf, complex *b, int ldb, complex *x, int ldx, float *ferr, float *berr, int *info);
void cporfs_64(char uplo, long n, long nrhs, complex *a, long lda, complex *af, long ldaf, complex *b, long ldb, complex *x, long ldx, float *ferr, float *berr, long *info);
cporfs improves the computed solution to a system of linear equations when the coefficient matrix is Hermitian positive definite, and provides error bounds and backward error estimates for the solution.
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
X(j)
(the j-th column of the solution matrix X).
If XTRUE is the true solution corresponding to X(j), FERR(j)
is an estimated upper bound for the magnitude of the largest
element in (X(j) - XTRUE) divided by the magnitude of the
largest element in X(j). The estimate is as reliable as
the estimate for RCOND, and is almost always a slight
overestimate of the true error.
X(j)
(i.e., the smallest relative change in
any element of A or B that makes X(j)
an exact solution).
dimension(2*N)
dimension(N)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value