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template<typename T>
void gtsv(integer *n, integer *nrhs, T *dl, T *d, T *du, T *b, integer *ldb, integer *info)# GTSV computes the solution to system of linear equations A * X = B for GT matrices.
Purpose:
GTSV solves the equation A*X = B, where A is an n by n tridiagonal matrix, by Gaussian elimination with partial pivoting. Note that the equation A**T*X = B may be solved by interchanging the order of the arguments DU and DL.
- Parameters:
N – [in]
N is INTEGER
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.
DL – [inout]
DL is REAL array, dimension (N-1)
On entry, DL must contain the (n-1) sub-diagonal elements of A.
On exit, DL is overwritten by the (n-2) elements of the second super-diagonal of the upper triangular matrix U from the LU factorization of A, in DL(1), …, DL(n-2).D – [inout]
D is REAL array, dimension (N)
On entry, D must contain the diagonal elements of A.
On exit, D is overwritten by the n diagonal elements of U.DU – [inout]
DU is REAL array, dimension (N-1)
On entry, DU must contain the (n-1) super-diagonal elements of A.
On exit, DU is overwritten by the (n-1) elements of the first super-diagonal of U.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, and the solution has not been computed. The factorization has not been completed unless i = N.