cgttrs-f(3)

cgttrs.f –

Synopsis

Functions/Subroutines

subroutine cgttrs (TRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB, INFO)
CGTTRS

Function/Subroutine Documentation

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

CGTTRS

Purpose:

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

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**H * X = B (Conjugate transpose)

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

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

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

DU2

 DU2 is COMPLEX 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 is COMPLEX 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 = -k, the k-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 cgttrs.f.

Author

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