CGESC2(l) ) CGESC2(l)NAME
CGESC2 - solve a system of linear equations A * X = scale* RHS with a
general N-by-N matrix A using the LU factorization with complete pivot‐
ing computed by CGETC2
SYNOPSIS
SUBROUTINE CGESC2( N, A, LDA, RHS, IPIV, JPIV, SCALE )
INTEGER LDA, N
REAL SCALE
INTEGER IPIV( * ), JPIV( * )
COMPLEX A( LDA, * ), RHS( * )
PURPOSE
CGESC2 solves a system of linear equations A * X = scale* RHS with a
general N-by-N matrix A using the LU factorization with complete pivot‐
ing computed by CGETC2.
ARGUMENTS
N (input) INTEGER
The number of columns of the matrix A.
A (input) COMPLEX array, dimension (LDA, N)
On entry, the LU part of the factorization of the n-by-n
matrix A computed by CGETC2: A = P * L * U * Q
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1, N).
RHS (input/output) COMPLEX array, dimension N.
On entry, the right hand side vector b. On exit, the solution
vector X.
IPIV (iput) INTEGER array, dimension (N).
The pivot indices; for 1 <= i <= N, row i of the matrix has
been interchanged with row IPIV(i).
JPIV (iput) 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) REAL
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.
LAPACK version 3.0 15 June 2000 CGESC2(l)
