

cla_lin_berr.f(3) LAPACK cla_lin_berr.f(3) NAME
cla_lin_berr.f  SYNOPSIS
Functions/Subroutines subroutine cla_lin_berr (N, NZ, NRHS, RES, AYB, BERR) CLA_LIN_BERR Function/Subroutine Documentation subroutine cla_lin_berr (integerN, integerNZ, integerNRHS, complex, dimension( n, nrhs )RES, real, dimension( n, nrhs )AYB, real, dimension( nrhs )BERR) CLA_LIN_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 vector Z. Parameters: N N is INTEGER The number of linear equations, i.e., the order of the matrix A. N >= 0. NZ NZ is INTEGER We add (NZ+1)*SLAMCH( 'Safe minimum' ) to R(i) in the numerator to guard against spuriously zero residuals. Default value is N. NRHS 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 RES is DOUBLE PRECISION array, dimension (N,NRHS) The residual matrix, i.e., the matrix R in the relative backward error formula above. AYB AYB is DOUBLE PRECISION 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 BERR is COMPLEX array, dimension (NRHS) The componentwise relative backward error from the formula above. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: November 2011 Definition at line 102 of file cla_lin_berr.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.1 Sun May 26 2013 cla_lin_berr.f(3)