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CentOS 7.0 - man page for dla_lin_berr (centos section 3)

dla_lin_berr.f(3)						      LAPACK							 dla_lin_berr.f(3)

NAME
dla_lin_berr.f -
SYNOPSIS
Functions/Subroutines subroutine dla_lin_berr (N, NZ, NRHS, RES, AYB, BERR) DLA_LIN_BERR computes a component-wise relative backward error. Function/Subroutine Documentation subroutine dla_lin_berr (integerN, integerNZ, integerNRHS, double precision, dimension( n, nrhs )RES, double precision, dimension( n, nrhs )AYB, double precision, dimension( nrhs )BERR) DLA_LIN_BERR computes a component-wise relative backward error. Purpose: DLA_LIN_BERR computes component-wise 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 component-wise 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 dla_gerfsx_extended.f). BERR BERR is DOUBLE PRECISION array, dimension (NRHS) The component-wise relative backward error from the formula above. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Definition at line 102 of file dla_lin_berr.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.2 Tue Sep 25 2012 dla_lin_berr.f(3)