GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
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zgetc2(l) |
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ZGETC2 - compute an LU factorization, using complete pivoting, of the n-by-n matrix A
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SUBROUTINE ZGETC2( |
N, A, LDA, IPIV, JPIV, INFO ) |
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INTEGER |
INFO, LDA, N |
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INTEGER |
IPIV( * ), JPIV( * ) |
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COMPLEX*16 |
A( LDA, * ) |
ZGETC2 computes an LU factorization, using complete pivoting, of the n-by-n matrix A. The factorization has the form A = P * L * U * Q, where P and Q are permutation matrices, L is lower triangular with unit diagonal elements and U is upper triangular.
This is a level 1 BLAS version of the algorithm.
N (input) INTEGER
The order of the matrix A. N >= 0.
A (input/output) COMPLEX*16 array, dimension (LDA, N)
On entry, the n-by-n matrix to be factored. On exit, the factors L and U from the factorization A = P*L*U*Q; the unit diagonal elements of L are not stored. If U(k, k) appears to be less than SMIN, U(k, k) is given the value of SMIN, giving a nonsingular perturbed system.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1, N).
IPIV (output) INTEGER array, dimension (N).
The pivot indices; for 1 <= i <= N, row i of the matrix has been interchanged with row IPIV(i).
JPIV (output) INTEGER array, dimension (N).
The pivot indices; for 1 <= j <= N, column j of the matrix has been interchanged with column JPIV(j).
INFO (output) INTEGER
= 0: successful exit
> 0: if INFO = k, U(k, k) is likely to produce overflow
if one tries to solve for x in Ax = b. So U is perturbed to
avoid the overflow.
Based on
contributions by
Bo Kagstrom and Peter Poromaa, Department of Computing
Science,
Umea University, S-901 87 Umea, Sweden.
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zgetc2(l) | |