NAMELAPACK-3 - 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
SYNOPSISSUBROUTINE ZGESC2( N, A, LDA, RHS, IPIV, JPIV, SCALE ) INTEGER LDA, N DOUBLE PRECISION SCALE INTEGER IPIV( * ), JPIV( * ) COMPLEX*16 A( LDA, * ), RHS( * )
PURPOSEZGESC2 solves a system of linear equations
ARGUMENTSN (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. 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 DETAILSBased on contributions by Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden. LAPACK auxiliary routine (versionMarch 2011 LAPACK-3(3)