dpttrs (l)  Linux Man Pages
dpttrs: solves a tridiagonal system of the form A * X = B using the L*D*Laq factorization of A computed by DPTTRF
Command to display dpttrs
manual in Linux: $ man l dpttrs
NAME
DPTTRS  solves a tridiagonal system of the form A * X = B using the L*D*Laq factorization of A computed by DPTTRF
SYNOPSIS
 SUBROUTINE DPTTRS(

N, NRHS, D, E, B, LDB, INFO )

INTEGER
INFO, LDB, N, NRHS

DOUBLE
PRECISION B( LDB, * ), D( * ), E( * )
PURPOSE
DPTTRS solves a tridiagonal system of the form
A
* X = B
using the L*D*Laq factorization of A computed by DPTTRF. 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) DOUBLE PRECISION array, dimension (N)

The n diagonal elements of the diagonal matrix D from the
L*D*Laq factorization of A.
 E (input) DOUBLE PRECISION 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) DOUBLE PRECISION 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 dpttrs
 dpttrs (3)
 dpttrf (l)  computes the L*D*Laq factorization of a real symmetric positive definite tridiagonal matrix A
 dptts2 (l)  solves a tridiagonal system of the form A * X = B using the L*D*Laq factorization of A computed by DPTTRF
 dptcon (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 DPTTRF
 dpteqr (l)  computes all eigenvalues and, optionally, eigenvectors of a symmetric positive definite tridiagonal matrix by first factoring the matrix using DPTTRF, and then calling DBDSQR to compute the singular values of the bidiagonal factor
 dptrfs (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
 dptsv (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
 dptsvx (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