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)