# cgesc2 (l) - Linux Man Pages

## 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 pivoting computed by CGETC2

## NAME

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 pivoting 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## 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 (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) 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 byBo Kagstrom and Peter Poromaa, Department of Computing Science,

Umea University, S-901 87 Umea, Sweden.