spttrs (l)  Linux Man Pages
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 (N1)

The (n1) 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 kth 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 1norm) 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 NbyN symmetric positive definite tridiagonal matrix, and X and B are NbyNRHS 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 NbyN symmetric positive definite tridiagonal matrix and X and B are NbyNRHS matrices