GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
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sgesv(l) |
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SGESV - compute the solution to a real system of linear equations A * X = B,
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SUBROUTINE SGESV( |
N, NRHS, A, LDA, IPIV, B, LDB, INFO ) |
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INTEGER |
INFO, LDA, LDB, N, NRHS |
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INTEGER |
IPIV( * ) |
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REAL |
A( LDA, * ), B( LDB, * ) |
SGESV computes the solution to a real system of linear equations A * X = B, where A is an N-by-N matrix and X and B are N-by-NRHS matrices.
The LU
decomposition with partial pivoting and row interchanges is
used to factor A as
A = P * L * U,
where P is a permutation matrix, L is unit lower triangular,
and U is upper triangular. The factored form of A is then
used to solve the system of equations A * X = B.
N (input) INTEGER
The number of linear equations, i.e., the order of the matrix A. N >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
A (input/output) REAL array, dimension (LDA,N)
On entry, the N-by-N coefficient matrix A. On exit, the factors L and U from the factorization A = P*L*U; the unit diagonal elements of L are not stored.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
IPIV (output) INTEGER array, dimension (N)
The pivot indices that define the permutation matrix P; row i of the matrix was interchanged with row IPIV(i).
B (input/output) REAL array, dimension (LDB,NRHS)
On entry, the N-by-NRHS matrix of right hand side matrix B. On exit, if INFO = 0, the N-by-NRHS solution matrix X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, U(i,i) is exactly zero. The
factorization has been completed, but the factor U is
exactly singular, so the solution could not be computed.
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sgesv(l) | |