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dla_syrcond.f(3) | LAPACK | dla_syrcond.f(3) |
NAME¶
dla_syrcond.f -SYNOPSIS¶
Functions/Subroutines¶
double precision function dla_syrcond (UPLO, N, A, LDA, AF, LDAF, IPIV, CMODE, C, INFO, WORK, IWORK)
Function/Subroutine Documentation¶
double precision function dla_syrcond (characterUPLO, integerN, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( ldaf, * )AF, integerLDAF, integer, dimension( * )IPIV, integerCMODE, double precision, dimension( * )C, integerINFO, double precision, dimension( * )WORK, integer, dimension( * )IWORK)¶
DLA_SYRCOND estimates the Skeel condition number for a symmetric indefinite matrix. Purpose:DLA_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.
UPLO
Author:
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 block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by DSYTRF.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 DSYTRF.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.
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
September 2012
Definition at line 147 of file dla_syrcond.f.
Author¶
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