dpttrs (3) Linux Manual Page

dpttrs.f –

Synopsis

Functions/Subroutines

subroutine dpttrs (N, NRHS, D, E, B, LDB, INFO)
DPTTRS

Function/Subroutine Documentation

subroutine dpttrs (integerN, integerNRHS, double precision, dimension( * )D, double precision, dimension( * )E, double precision, dimension( ldb, * )B, integerLDB, integerINFO)

DPTTRS

Purpose:

 DPTTRS solves a tridiagonal system of the form

 A * X = B

 using the L*D*L**T 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.

 

Parameters:

N

 N is INTEGER

 The order of the tridiagonal matrix A. N >= 0.

NRHS

 NRHS is INTEGER

 The number of right hand sides, i.e., the number of columns

 of the matrix B. NRHS >= 0.

D

 D is DOUBLE PRECISION array, dimension (N)

 The n diagonal elements of the diagonal matrix D from the

 L*D*L**T factorization of A.

E

 E is DOUBLE PRECISION array, dimension (N-1)

 The (n-1) subdiagonal elements of the unit bidiagonal factor

 L from the L*D*L**T factorization of A. E can also be regarded

 as the superdiagonal of the unit bidiagonal factor U from the

 factorization A = U**T*D*U.

B

 B is 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

 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 110 of file dpttrs.f.

Author

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