NAME

       sla_syrcond.f -

SYNOPSIS

   Functions/Subroutines
       real function sla_syrcond (UPLO, N, A, LDA, AF, LDAF, IPIV, CMODE, C, INFO, WORK, IWORK)
           SLA_SYRCOND estimates the Skeel condition number for a symmetric indefinite matrix.

Function/Subroutine Documentation

   real function sla_syrcond (characterUPLO, integerN, real, dimension( lda, * )A, integerLDA,
       real, dimension( ldaf, * )AF, integerLDAF, integer, dimension( * )IPIV, integerCMODE,
       real, dimension( * )C, integerINFO, real, dimension( * )WORK, integer, dimension( *
       )IWORK)
       SLA_SYRCOND estimates the Skeel condition number for a symmetric indefinite matrix.

       Purpose:

               SLA_SYRCOND 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.

       Parameters:
           UPLO

                     UPLO is CHARACTER*1
                  = 'U':  Upper triangle of A is stored;
                  = 'L':  Lower triangle of A is stored.

           N

                     N is INTEGER
                The number of linear equations, i.e., the order of the
                matrix A.  N >= 0.

           A

                     A is REAL array, dimension (LDA,N)
                On entry, the N-by-N matrix A.

           LDA

                     LDA is INTEGER
                The leading dimension of the array A.  LDA >= max(1,N).

           AF

                     AF is REAL array, dimension (LDAF,N)
                The block diagonal matrix D and the multipliers used to
                obtain the factor U or L as computed by SSYTRF.

           LDAF

                     LDAF is INTEGER
                The leading dimension of the array AF.  LDAF >= max(1,N).

           IPIV

                     IPIV is INTEGER array, dimension (N)
                Details of the interchanges and the block structure of D
                as determined by SSYTRF.

           CMODE

                     CMODE is INTEGER
                Determines op2(C) in the formula op(A) * op2(C) as follows:
                CMODE =  1    op2(C) = C
                CMODE =  0    op2(C) = I
                CMODE = -1    op2(C) = inv(C)

           C

                     C is REAL array, dimension (N)
                The vector C in the formula op(A) * op2(C).

           INFO

                     INFO is INTEGER
                  = 0:  Successful exit.
                i > 0:  The ith argument is invalid.

           WORK

                     WORK is REAL array, dimension (3*N).
                Workspace.

           IWORK

                     IWORK is INTEGER array, dimension (N).
                Workspace.

       Author:
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Date:
           September 2012

       Definition at line 146 of file sla_syrcond.f.

Author

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