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function test15
%TEST15 test cs_amd
%
% Example:
% test15
% See also: testall
% CXSparse, Copyright (c) 2006-2022, Timothy A. Davis. All Rights Reserved.
% SPDX-License-Identifier: LGPL-2.1+
rand ('state', 0) ;
randn ('state', 0) ;
clf
for trials = 1:100
n = fix (200 * rand (1)) ;
d = 0.05 * rand (1) ;
A = sprandn (n, n, d) ;
% add a randomly placed dense column
k = fix (n * rand (1)) ;
k = max (1, k) ;
k = min (n, k) ;
if (n > 0)
A (:,k) = 1 ;
end
if (~ispc)
if (rand ( ) > .5)
A = A + 1i * sprand (A) ;
end
end
try
p0 = amd (A) ;
catch
p0 = symamd (A) ;
end
p1 = cs_amd (A) ;
if (any (sort (p1) ~= 1:n))
error ('not perm!') ;
end
C = A+A' + speye (n) ;
lnz0 = sum (symbfact (C (p0,p0))) ;
lnz1 = sum (symbfact (C (p1,p1))) ;
subplot (1,3,1) ; spy (C)
subplot (1,3,2) ; spy (C (p0,p0))
subplot (1,3,3) ; spy (C (p1,p1))
fprintf ('n %4d nz %6d lnz %6d %6d\n', n, nnz(A), lnz0, lnz1) ;
drawnow
end
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