spttrf.f man page

spttrf.f —

Synopsis

Functions/Subroutines

subroutine spttrf (N, D, E, INFO)
SPTTRF

Function/Subroutine Documentation

subroutine spttrf (integerN, real, dimension( * )D, real, dimension( * )E, integerINFO)

SPTTRF

Purpose:

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

E

E is REAL 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:

November 2011

Definition at line 92 of file spttrf.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK