cptsv-f(3)

cptsv.f –

Synopsis

Functions/Subroutines

subroutine cptsv (N, NRHS, D, E, B, LDB, INFO)
CPTSV computes the solution to system of linear equations A * X = B for PT matrices

Function/Subroutine Documentation

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

CPTSV computes the solution to system of linear equations A * X = B for PT matrices

Purpose:

 CPTSV computes the solution to a complex system of linear equations
 A*X = B, where A is an N-by-N Hermitian positive definite tridiagonal
 matrix, and X and B are N-by-NRHS matrices.
 A is factored as A = L*D*L**H, and the factored form of A is then
 used to solve the system of equations.

Parameters:

 N is INTEGER
 The order of the 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 is REAL array, dimension (N)
 On entry, the n diagonal elements of the tridiagonal matrix
 A. On exit, the n diagonal elements of the diagonal matrix
 D from the factorization A = L*D*L**H.

 E is COMPLEX array, dimension (N-1)
 On entry, the (n-1) subdiagonal elements of the tridiagonal
 matrix A. On exit, the (n-1) subdiagonal elements of the
 unit bidiagonal factor L from the L*D*L**H factorization of
 A. E can also be regarded as the superdiagonal of the unit
 bidiagonal factor U from the U**H*D*U factorization of A.

 B is COMPLEX array, dimension (LDB,NRHS)
 On entry, the N-by-NRHS right hand side matrix B.
 On exit, if INFO = 0, the N-by-NRHS solution matrix 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
 > 0: if INFO = i, the leading minor of order i is not
 positive definite, and the solution has not been
 computed. The factorization has not been completed
 unless i = N.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 116 of file cptsv.f.

Author

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