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function test26
%TEST26 test cs_dmsol and cs_dmspy
%
% Example:
% test26
% See also: testall
% Copyright 2006-2007, Timothy A. Davis.
% http://www.cise.ufl.edu/research/sparse
clear functions
randn ('state', 0) ;
rand ('state', 0) ;
clf
ntrials = 1000 ;
e1 = zeros (ntrials,1) ;
e2 = zeros (ntrials,1) ;
for trials = 1:ntrials
m = fix (100 * rand (1)) ;
n = fix (100 * rand (1)) ;
% d = 0.1 * rand (1) ;
d = rand (1) * 4 * max (m,n) / max (m*n,1) ;
A = sprandn (m,n,d) ;
% S = sprandn (m,m,d) + speye (m) ;
subplot (1,3,2) ; spy (A) ;
subplot (1,3,3) ; cs_dmspy (A) ;
b = rand (m,1) ;
x1 = A\b ;
x2 = cs_dmsol (A,b) ;
err1 = norm (A*x1-b) ;
err2 = norm (A*x2-b) ;
lerr1 = log10 (max (err1, eps)) ;
lerr2 = log10 (max (err2, eps)) ;
fprintf ('rank: %3d %3d err %6.2e %6.2e : %6.1f\n', ...
sprank(A), rank(full(A)), err1, err2, lerr1 - lerr2) ;
if (isnan (err1))
lerr1 = 10 ;
end
if (isnan (err2))
lerr2 = 10 ;
end
if (lerr2 > lerr1 + 5)
% pause
end
e1 (trials) = lerr1 ;
e2 (trials) = lerr2 ;
subplot (1,3,1) ; plot (e1, e2, 'o', [-16 10], [-16 10], 'r') ;
xlabel ('MATLAB error') ;
ylabel ('dmsol error') ;
drawnow
% pause
end
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