 |
LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
|
|
LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
|
| subroutine sptsv | ( | integer | N, |
| integer | NRHS, | ||
| real, dimension( * ) | D, | ||
| real, dimension( * ) | E, | ||
| real, dimension( ldb, * ) | B, | ||
| integer | LDB, | ||
| integer | INFO | ||
| ) |
SPTSV computes the solution to system of linear equations A * X = B for PT matrices
Download SPTSV + dependencies [TGZ] [ZIP] [TXT]
SPTSV computes the solution to a real system of linear equations A*X = B, where A is an N-by-N symmetric positive definite tridiagonal matrix, and X and B are N-by-NRHS matrices. A is factored as A = L*D*L**T, and the factored form of A is then used to solve the system of equations.
| [in] | N | N is INTEGER
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] | D | D is REAL array, dimension (N)
On entry, the n diagonal elements of the tridiagonal matrix
A. On exit, the n diagonal elements of the diagonal matrix
D from the factorization A = L*D*L**T. |
| [in,out] | E | E is REAL array, dimension (N-1)
On entry, the (n-1) subdiagonal elements of the tridiagonal
matrix A. On exit, the (n-1) subdiagonal elements of the
unit bidiagonal factor L from the L*D*L**T factorization of
A. (E can also be regarded as the superdiagonal of the unit
bidiagonal factor U from the U**T*D*U factorization of A.) |
| [in,out] | B | B is REAL array, dimension (LDB,NRHS)
On entry, the N-by-NRHS 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, the leading minor of order i is not
positive definite, and the solution has not been
computed. The factorization has not been completed
unless i = N. |
1.9.4