SRC/dla_porcond.f(3)       Library Functions Manual       SRC/dla_porcond.f(3)

NAME
       SRC/dla_porcond.f

SYNOPSIS
   Functions/Subroutines
       double precision function dla_porcond (uplo, n, a, lda, af, ldaf,
           cmode, c, info, work, iwork)
           DLA_PORCOND estimates the Skeel condition number for a symmetric
           positive-definite matrix.

Function/Subroutine Documentation
   double precision function dla_porcond (character uplo, integer n, double
       precision, dimension( lda, * ) a, integer lda, double precision,
       dimension( ldaf, * ) af, integer ldaf, integer cmode, double precision,
       dimension( * ) c, integer info, double precision, dimension( * ) work,
       integer, dimension( * ) iwork)
       DLA_PORCOND estimates the Skeel condition number for a symmetric
       positive-definite matrix.

       Purpose:


           !>
           !>    DLA_PORCOND 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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (LDAF,N)
           !>     The triangular factor U or L from the Cholesky factorization
           !>     A = U**T*U or A = L*L**T, as computed by DPOTRF.
           !>

           LDAF

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

           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 DOUBLE PRECISION 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 DOUBLE PRECISION 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.

       Definition at line 139 of file dla_porcond.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0            SRC/dla_porcond.f(3)