SLA_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.

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 triangular factor U or L from the Cholesky factorization


     A = U**T*U or A = L*L**T, as computed by SPOTRF.

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 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.

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

September 2012