spttrs (l) - Linux Manuals
spttrs: solves a tridiagonal system of the form A * X = B using the L*D*Laq factorization of A computed by SPTTRF
Command to display spttrs manual in Linux: $ man l spttrs
NAME
SPTTRS - solves a tridiagonal system of the form A * X = B using the L*D*Laq factorization of A computed by SPTTRF
SYNOPSIS
- SUBROUTINE SPTTRS(
-
N, NRHS, D, E, B, LDB, INFO )
-
INTEGER
INFO, LDB, N, NRHS
-
REAL
B( LDB, * ), D( * ), E( * )
PURPOSE
SPTTRS solves a tridiagonal system of the form
A
* X = B
using the L*D*Laq factorization of A computed by SPTTRF. D is a
diagonal matrix specified in the vector D, L is a unit bidiagonal
matrix whose subdiagonal is specified in the vector E, and X and B
are N by NRHS matrices.
ARGUMENTS
- N (input) INTEGER
-
The order of the tridiagonal 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.
- D (input) REAL array, dimension (N)
-
The n diagonal elements of the diagonal matrix D from the
L*D*Laq factorization of A.
- E (input) REAL array, dimension (N-1)
-
The (n-1) subdiagonal elements of the unit bidiagonal factor
L from the L*D*Laq factorization of A. E can also be regarded
as the superdiagonal of the unit bidiagonal factor U from the
factorization A = Uaq*D*U.
- B (input/output) REAL array, dimension (LDB,NRHS)
-
On entry, the right hand side vectors B for the system of
linear equations.
On exit, the solution vectors, X.
- LDB (input) INTEGER
-
The leading dimension of the array B. LDB >= max(1,N).
- INFO (output) INTEGER
-
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value
Pages related to spttrs
- spttrs (3)
- spttrf (l) - computes the L*D*Laq factorization of a real symmetric positive definite tridiagonal matrix A
- sptts2 (l) - solves a tridiagonal system of the form A * X = B using the L*D*Laq factorization of A computed by SPTTRF
- sptcon (l) - computes the reciprocal of the condition number (in the 1-norm) of a real symmetric positive definite tridiagonal matrix using the factorization A = L*D*L**T or A = U**T*D*U computed by SPTTRF
- spteqr (l) - computes all eigenvalues and, optionally, eigenvectors of a symmetric positive definite tridiagonal matrix by first factoring the matrix using SPTTRF, and then calling SBDSQR to compute the singular values of the bidiagonal factor
- sptrfs (l) - improves the computed solution to a system of linear equations when the coefficient matrix is symmetric positive definite and tridiagonal, and provides error bounds and backward error estimates for the solution
- sptsv (l) - 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
- sptsvx (l) - uses the factorization A = L*D*L**T to compute 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