psdttrf (3)

Compute a lu factorization of an n-by-n real tridiagonal diagonally dominant-like distributed matrix a(1:n, ja:ja+n-1)

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  4. psdttrf: Compute a lu factorization of an n-by-n real tridiagonal diagonally dominant-like distributed matrix a(1:n, ja:ja+n-1)
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  4. psdttrf: Compute a lu factorization of an n-by-n real tridiagonal diagonally dominant-like distributed matrix a(1:n, ja:ja+n-1)

SYNOPSIS

SUBROUTINE PSDTTRF(

N, DL, D, DU, JA, DESCA, AF, LAF, WORK, LWORK, INFO )

INTEGER

INFO, JA, LAF, LWORK, N

INTEGER

DESCA( * )

REAL

AF( * ), D( * ), DL( * ), DU( * ), WORK( * )

PURPOSE

PSDTTRF computes a LU factorization of an N-by-N real tridiagonal diagonally dominant-like distributed matrix A(1:N, JA:JA+N-1). Reordering is used to increase parallelism in the factorization. This reordering results in factors that are DIFFERENT from those produced by equivalent sequential codes. These factors cannot be used directly by users; however, they can be used in

subsequent calls to PSDTTRS to solve linear systems.

The factorization has the form

        P A(1:N, JA:JA+N-1) P^T = L U

where U is a tridiagonal upper triangular matrix and L is tridiagonal lower triangular, and P is a permutation matrix.