SGTTS2 (3) Linux Manual Page

sgtts2.f –

Synopsis

Functions/Subroutines

subroutine sgtts2 (ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB)
SGTTS2 solves a system of linear equations with a tridiagonal matrix using the LU factorization computed by sgttrf.

Function/Subroutine Documentation

subroutine sgtts2 (integerITRANS, integerN, integerNRHS, real, dimension( * )DL, real, dimension( * )D, real, dimension( * )DU, real, dimension( * )DU2, integer, dimension( * )IPIV, real, dimension( ldb, * )B, integerLDB)

SGTTS2 solves a system of linear equations with a tridiagonal matrix using the LU factorization computed by sgttrf.

Purpose:

 SGTTS2 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:

ITRANS

 ITRANS is INTEGER

 Specifies the form of the system of equations.

 = 0: A * X = B (No transpose)

 = 1: A**T* X = B (Transpose)

 = 2: 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).

 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 129 of file sgtts2.f.

Author

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