Mercurial > octave-nkf
view liboctave/UMFPACK/UMFPACK/MATLAB/luflop.m @ 5164:57077d0ddc8e
[project @ 2005-02-25 19:55:24 by jwe]
author | jwe |
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date | Fri, 25 Feb 2005 19:55:28 +0000 |
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function f = luflop (L, U) %LUFLOP % % f = luflop (L, U) % % Given an LU factorization, compute how many flops took to compute it. This % is the same as (assuming U has a zero-free diagonal): % % Lnz = full (sum (spones (L))) - 1 ; % Unz = full (sum (spones (U')))' - 1 ; % f = 2*Lnz*Unz + sum (Lnz) ; % % except that no extra workspace is allocated for spones (L) and spones (U). % L and U must be sparse. % % Note: the above expression has a subtle undercount when exact numerical % cancelation occurs. Try [L,U,P] = lu (sparse (ones (10))) and then % luflop (L,U). % UMFPACK Version 4.4, Copyright (c) 2005 by Timothy A. Davis. % All Rights Reserved. Type umfpack_details for License. help luflop error ('luflop mexFunction not found! Use umfpack_make to compile luflop.') ;