cla_lin_berr - wise relative backward error
SUBROUTINE CLA_LIN_BERR (N, NZ, NRHS, RES, AYB, BERR) INTEGER N, NZ, NRHS REAL AYB(N,NRHS), BERR(NRHS) COMPLEX RES(N,NRHS) SUBROUTINE CLA_LIN_BERR_64 (N, NZ, NRHS, RES, AYB, BERR) INTEGER*8 N, NZ, NRHS REAL AYB(N,NRHS), BERR(NRHS) COMPLEX RES(N,NRHS) F95 INTERFACE SUBROUTINE LA_LIN_BERR (N, NZ, NRHS, RES, AYB, BERR) REAL, DIMENSION(:,:) :: AYB INTEGER :: N, NZ, NRHS REAL, DIMENSION(:) :: BERR COMPLEX, DIMENSION(:,:) :: RES SUBROUTINE LA_LIN_BERR_64 (N, NZ, NRHS, RES, AYB, BERR) REAL, DIMENSION(:,:) :: AYB INTEGER(8) :: N, NZ, NRHS REAL, DIMENSION(:) :: BERR COMPLEX, DIMENSION(:,:) :: RES C INTERFACE #include <sunperf.h> void cla_lin_berr (int n, int nz, int nrhs, floatcomplex *res, float *ayb, float *berr); void cla_lin_berr_64 (long n, long nz, long nrhs, floatcomplex *res, float *ayb, float *berr);
Oracle Solaris Studio Performance Library cla_lin_berr(3P) NAME cla_lin_berr - compute a component-wise relative backward error SYNOPSIS SUBROUTINE CLA_LIN_BERR (N, NZ, NRHS, RES, AYB, BERR) INTEGER N, NZ, NRHS REAL AYB(N,NRHS), BERR(NRHS) COMPLEX RES(N,NRHS) SUBROUTINE CLA_LIN_BERR_64 (N, NZ, NRHS, RES, AYB, BERR) INTEGER*8 N, NZ, NRHS REAL AYB(N,NRHS), BERR(NRHS) COMPLEX RES(N,NRHS) F95 INTERFACE SUBROUTINE LA_LIN_BERR (N, NZ, NRHS, RES, AYB, BERR) REAL, DIMENSION(:,:) :: AYB INTEGER :: N, NZ, NRHS REAL, DIMENSION(:) :: BERR COMPLEX, DIMENSION(:,:) :: RES SUBROUTINE LA_LIN_BERR_64 (N, NZ, NRHS, RES, AYB, BERR) REAL, DIMENSION(:,:) :: AYB INTEGER(8) :: N, NZ, NRHS REAL, DIMENSION(:) :: BERR COMPLEX, DIMENSION(:,:) :: RES C INTERFACE #include <sunperf.h> void cla_lin_berr (int n, int nz, int nrhs, floatcomplex *res, float *ayb, float *berr); void cla_lin_berr_64 (long n, long nz, long nrhs, floatcomplex *res, float *ayb, float *berr); PURPOSE cla_lin_berr computes componentwise relative backward error from the formula max(i) (abs(R(i)) / (abs(op(A_s))*abs(Y) + abs(B_s))(i)) where abs(Z) is the componentwise absolute value of the matrix or vec- tor Z. ARGUMENTS N (input) N is INTEGER The number of linear equations, i.e., the order of the matrix A. N >= 0. NZ (input) NZ is INTEGER We add (NZ+1)*SLAMCH( 'Safe minimum' ) to R(i) in the numera- tor to guard against spuriously zero residuals. Default value is N. NRHS (input) NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrices AYB, RES, and BERR. NRHS >= 0. RES (input) RES is REAL array, dimension (N,NRHS) The residual matrix, i.e., the matrix R in the relative back- ward error formula above. AYB (input) AYB is REAL array, dimension (N, NRHS) The denominator in the relative backward error formula above, i.e., the matrix abs(op(A_s))*abs(Y) + abs(B_s). The matrices A, Y, and B are from iterative refinement (see cla_gerfsx_extended.f). BERR (output) BERR is COMPLEX array, dimension (NRHS) The componentwise relative backward error from the formula above. 7 Nov 2015 cla_lin_berr(3P)