SLA_PORCOND (3)  Linux Manuals
NAME
sla_porcond.f 
SYNOPSIS
Functions/Subroutines
REAL function sla_porcond (UPLO, N, A, LDA, AF, LDAF, CMODE, C, INFO, WORK, IWORK)
SLA_PORCOND estimates the Skeel condition number for a symmetric positivedefinite matrix.
Function/Subroutine Documentation
REAL function sla_porcond (characterUPLO, integerN, real, dimension( lda, * )A, integerLDA, real, dimension( ldaf, * )AF, integerLDAF, integerCMODE, real, dimension( * )C, integerINFO, real, dimension( * )WORK, integer, dimension( * )IWORK)
SLA_PORCOND estimates the Skeel condition number for a symmetric positivedefinite matrix.
Purpose:

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 infinitynorm condition number.
Parameters:

UPLO
UPLO is CHARACTER*1 = 'U': Upper triangle of A is stored; = 'L': Lower triangle of A is stored.
NN is INTEGER The number of linear equations, i.e., the order of the matrix A. N >= 0.
AA is REAL array, dimension (LDA,N) On entry, the NbyN matrix A.
LDALDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).
AFAF 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.
LDAFLDAF is INTEGER The leading dimension of the array AF. LDAF >= max(1,N).
CMODECMODE 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)
CC is REAL array, dimension (N) The vector C in the formula op(A) * op2(C).
INFOINFO is INTEGER = 0: Successful exit. i > 0: The ith argument is invalid.
WORKWORK is REAL array, dimension (3*N). Workspace.
IWORKIWORK 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 140 of file sla_porcond.f.
Author
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