Provided by: liblapack-doc_3.3.1-1_all bug

NAME

       LAPACK-3  -  CLA_LIN_BERR  compute 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

SYNOPSIS

       SUBROUTINE CLA_LIN_BERR ( N, NZ, NRHS, RES, AYB, BERR )

           IMPLICIT            NONE

           INTEGER             N, NZ, NRHS

           REAL                AYB( N, NRHS ), BERR( NRHS )

           COMPLEX             RES( N, NRHS )

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.
           N       (input) INTEGER
           The number of linear equations, i.e., the order of the
           matrix A.  N >= 0.
           NZ      (input) 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    (input) INTEGER
           The number of right hand sides, i.e., the number of columns
           of the matrices AYB, RES, and BERR.  NRHS >= 0.
           RES    (input) DOUBLE PRECISION array, dimension (N,NRHS)
           The residual matrix, i.e., the matrix R in the relative backward
           error formula above.
           AYB    (input) 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   (output) COMPLEX array, dimension (NRHS)
           The componentwise relative backward error from the formula above.

    LAPACK routine (version 3.2.2)          April 2011                      CLA_LIN_BERR(3lapack)