cgesv()

subroutine cgesv	(	integer	n,
		integer	nrhs,
		complex, dimension( lda, * )	a,
		integer	lda,
		integer, dimension( * )	ipiv,
		complex, dimension( ldb, * )	b,
		integer	ldb,
		integer	info )

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Purpose:

!>
!> CGESV computes the solution to a complex 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.
!> 

Parameters

[in]	N	!> N is INTEGER !> The number of linear equations, i.e., the order of the !> matrix A. N >= 0. !>
[in]	NRHS	!> NRHS is INTEGER !> The number of right hand sides, i.e., the number of columns !> of the matrix B. NRHS >= 0. !>
[in,out]	A	!> A is COMPLEX 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. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
[out]	IPIV	!> IPIV is INTEGER array, dimension (N) !> The pivot indices that define the permutation matrix P; !> row i of the matrix was interchanged with row IPIV(i). !>
[in,out]	B	!> B is COMPLEX 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. !>
[in]	LDB	!> LDB is INTEGER !> The leading dimension of the array B. LDB >= max(1,N). !>
[out]	INFO	!> INFO is 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. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.