sgttrs.f man page

sgttrs.f —

Synopsis

Functions/Subroutines

subroutine sgttrs (TRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB, INFO)
SGTTRS

Function/Subroutine Documentation

subroutine sgttrs (characterTRANS, integerN, integerNRHS, real, dimension( * )DL, real, dimension( * )D, real, dimension( * )DU, real, dimension( * )DU2, integer, dimension( * )IPIV, real, dimension( ldb, * )B, integerLDB, integerINFO)

SGTTRS

Purpose:

SGTTRS solves one of the systems of equations
   A*X = B  or  A**T*X = B,
with a tridiagonal matrix A using the LU factorization computed
by SGTTRF.

Parameters:

TRANS

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

N

N is INTEGER
The order of the matrix A.

NRHS

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

DL

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

D

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

DU

DU is REAL array, dimension (N-1)
The (n-1) elements of the first super-diagonal of U.

DU2

DU2 is REAL array, dimension (N-2)
The (n-2) elements of the second super-diagonal of U.

IPIV

IPIV is 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

B is REAL 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

LDB is INTEGER
The leading dimension of the array B.  LDB >= max(1,N).

INFO

INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 138 of file sgttrs.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

sgttrs(3) is an alias of sgttrs.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK