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dla_gercond.3lapack

NAME

DLA_GERCOND - DLA_GERCOND estimate the Skeel condition number of op(A) * op2(C) where op2 is determined by CMODE as follows CMODE = 1 op2(C) = C CMODE = 0 op2(C) = I CMODE = -1 op2(C) = inv(C) The Skeel condition number cond(A) = norminf( |inv(A)||A| ) is computed by computing scaling factors R such that diag(R)*A*op2(C) is row equilibrated and computing the standard infinity-norm condition number

SYNOPSIS

DOUBLE PRECISION

FUNCTION DLA_GERCOND ( TRANS, N, A, LDA, AF, LDAF, IPIV, CMODE, C, INFO, WORK, IWORK )

    

IMPLICIT NONE

    

CHARACTER TRANS

    

INTEGER N, LDA, LDAF, INFO, CMODE

    

INTEGER IPIV( * ), IWORK( * )

    

DOUBLE PRECISION A( LDA, * ), AF( LDAF, * ), WORK( * ), C( * )

PURPOSE

   DLA_GERCOND estimates the Skeel condition number of op(A) * op2(C)
   where op2 is determined by CMODE as follows
   CMODE =  1    op2(C) = C
   CMODE =  0    op2(C) = I
   CMODE = -1    op2(C) = inv(C)
   The Skeel condition number cond(A) = norminf( |inv(A)||A| )
   is computed by computing scaling factors R such that
   diag(R)*A*op2(C) is row equilibrated and computing the standard
   infinity-norm condition number.

ARGUMENTS

WORK DOUBLE PRECISION workspace of size 3*N, and

IWORK INTEGER workspace of size N.