dpttrf.f man page

dpttrf.f —

Synopsis

Functions/Subroutines

subroutine dpttrf (N, D, E, INFO)
DPTTRF

Function/Subroutine Documentation

subroutine dpttrf (integerN, double precision, dimension( * )D, double precision, dimension( * )E, integerINFO)

DPTTRF

Purpose:

DPTTRF computes the L*D*L**T factorization of a real symmetric
positive definite tridiagonal matrix A.  The factorization may also
be regarded as having the form A = U**T*D*U.

Parameters:

N

N is INTEGER
The order of the matrix A.  N >= 0.

D

D is DOUBLE PRECISION 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 L*D*L**T factorization of A.

E

E is DOUBLE PRECISION 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**T factorization of A.
E can also be regarded as the superdiagonal of the unit
bidiagonal factor U from the U**T*D*U factorization of A.

INFO

INFO is INTEGER
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value
> 0: if INFO = k, the leading minor of order k is not
     positive definite; if k < N, the factorization could not
     be completed, while if k = N, the factorization was
     completed, but D(N) <= 0.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 92 of file dpttrf.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK