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template<typename T>
void gesv(integer *n, integer *nrhs, T *a, integer *lda, integer *ipiv, T *b, integer *ldb, integer *info)# GESV computes the solution to a real system of linear equations.
Purpose:
GESV 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.
- Parameters:
N – [in]
N is INTEGER
The number of linear equations, i.e., the order of the matrix A. N >= 0.
NRHS – [in]
NRHS is INTEGER
The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
@parm[in,out] A A is 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 – [in]
LDA is INTEGER
The leading dimension of the array A. LDA >= fla_max(1,N).
IPIV – [out]
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).
B – [inout]
B is 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 – [in]
LDB is INTEGER
The leading dimension of the array B. LDB >= fla_max(1,N).
INFO – [out]
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.