cpttrs.f man page

cpttrs.f —

Synopsis

Functions/Subroutines

subroutine cpttrs (UPLO, N, NRHS, D, E, B, LDB, INFO)
CPTTRS

Function/Subroutine Documentation

subroutine cpttrs (characterUPLO, integerN, integerNRHS, real, dimension( * )D, complex, dimension( * )E, complex, dimension( ldb, * )B, integerLDB, integerINFO)

CPTTRS

Purpose:

CPTTRS solves a tridiagonal system of the form
   A * X = B
using the factorization A = U**H*D*U or A = L*D*L**H computed by CPTTRF.
D is a diagonal matrix specified in the vector D, U (or L) is a unit
bidiagonal matrix whose superdiagonal (subdiagonal) is specified in
the vector E, and X and B are N by NRHS matrices.

Parameters:

UPLO

UPLO is CHARACTER*1
Specifies the form of the factorization and whether the
vector E is the superdiagonal of the upper bidiagonal factor
U or the subdiagonal of the lower bidiagonal factor L.
= 'U':  A = U**H*D*U, E is the superdiagonal of U
= 'L':  A = L*D*L**H, E is the subdiagonal of L

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 REAL array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
factorization A = U**H*D*U or A = L*D*L**H.

E

E is COMPLEX array, dimension (N-1)
If UPLO = 'U', the (n-1) superdiagonal elements of the unit
bidiagonal factor U from the factorization A = U**H*D*U.
If UPLO = 'L', the (n-1) subdiagonal elements of the unit
bidiagonal factor L from the factorization A = L*D*L**H.

B

B is REAL 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 122 of file cpttrs.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK