ZGESC2(3S)ZGESC2(3S)NAMEZGESC2 - solve a system of linear equations A * X = scale* RHS with a
general N-by-N matrix A using the LU factorization with complete pivoting
computed by ZGETC2
SYNOPSIS
SUBROUTINE ZGESC2( N, A, LDA, RHS, IPIV, JPIV, SCALE )
INTEGER LDA, N
DOUBLE PRECISION SCALE
INTEGER IPIV( * ), JPIV( * )
COMPLEX*16 A( LDA, * ), RHS( * )
IMPLEMENTATION
These routines are part of the SCSL Scientific Library and can be loaded
using either the -lscs or the -lscs_mp option. The -lscs_mp option
directs the linker to use the multi-processor version of the library.
When linking to SCSL with -lscs or -lscs_mp, the default integer size is
4 bytes (32 bits). Another version of SCSL is available in which integers
are 8 bytes (64 bits). This version allows the user access to larger
memory sizes and helps when porting legacy Cray codes. It can be loaded
by using the -lscs_i8 option or the -lscs_i8_mp option. A program may use
only one of the two versions; 4-byte integer and 8-byte integer library
calls cannot be mixed.
PURPOSEZGESC2 solves a system of linear equations A * X = scale* RHS with a
general N-by-N matrix A using the LU factorization with complete pivoting
computed by ZGETC2.
ARGUMENTS
N (input) INTEGER
The number of columns of the matrix A.
A (input) COMPLEX*16 array, dimension (LDA, N)
On entry, the LU part of the factorization of the n-by-n matrix
A computed by ZGETC2: A = P * L * U * Q
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1, N).
RHS (input/output) COMPLEX*16 array, dimension N.
On entry, the right hand side vector b. On exit, the solution
vector X.
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ZGESC2(3S)ZGESC2(3S)
IPIV (input) INTEGER array, dimension (N).
The pivot indices; for 1 <= i <= N, row i of the matrix has been
interchanged with row IPIV(i).
JPIV (input) INTEGER array, dimension (N).
The pivot indices; for 1 <= j <= N, column j of the matrix has
been interchanged with column JPIV(j).
SCALE (output) DOUBLE PRECISION
On exit, SCALE contains the scale factor. SCALE is chosen 0 <=
SCALE <= 1 to prevent owerflow in the solution.
FURTHER DETAILS
Based on contributions by
Bo Kagstrom and Peter Poromaa, Department of Computing Science,
Umea University, S-901 87 Umea, Sweden.
SEE ALSOINTRO_LAPACK(3S), INTRO_SCSL(3S)
This man page is available only online.
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