Function Dgttrs

Part of:

package f77
( dgttrs < trans > < n > < nrhs > < dl > < d > < du > < du2 > < ipiv > < b > < ldb > < info > )
-- LAPACK routine (version 3.2) --
-- LAPACK is a software package provided by Univ. of Tennessee, --
-- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
November 2006

.. Scalar Arguments ..
CHARACTER TRANS
INTEGER INFO, LDB, N, NRHS
..
.. Array Arguments ..
INTEGER IPIV( * )
DOUBLE PRECISION B( LDB, * ), D( * ), DL( * ), DU( * ), DU2( * )
..

Purpose
=======

DGTTRS solves one of the systems of equations
A*X = B or A'*X = B,
with a tridiagonal matrix A using the LU factorization computed
by DGTTRF.

Arguments
=========

TRANS (input) CHARACTER*1
Specifies the form of the system of equations.
= 'N': A * X = B (No transpose)
= 'T': A'* X = B (Transpose)
= 'C': A'* X = B (Conjugate transpose = Transpose)

N (input) INTEGER
The order of the matrix A.

NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.

DL (input) DOUBLE PRECISION array, dimension (N-1)
The (n-1) multipliers that define the matrix L from the
LU factorization of A.

D (input) DOUBLE PRECISION array, dimension (N)
The n diagonal elements of the upper triangular matrix U from
the LU factorization of A.

DU (input) DOUBLE PRECISION array, dimension (N-1)
The (n-1) elements of the first super-diagonal of U.

DU2 (input) DOUBLE PRECISION array, dimension (N-2)
The (n-2) elements of the second super-diagonal of U.

IPIV (input) INTEGER array, dimension (N)
The pivot indices; for 1 <= i <= n, row i of the matrix was
interchanged with row IPIV(i). IPIV(i) will always be either
i or i+1; IPIV(i) = i indicates a row interchange was not
required.

B (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
On entry, the matrix of right hand side vectors B.
On exit, B is overwritten by 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 = -i, the i-th argument had an illegal value