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function test_randperms
%TEST_RANDPERMS test random permutations
% Example:
% test_randperms
% See also: testall
% Copyright 2006-2007, Timothy A. Davis.
% http://www.cise.ufl.edu/research/sparse
rand ('state', 0)
for trial = 1:100
m = fix (30 * rand (1)) ;
n = fix (30 * rand (1)) ;
d = rand (1) ;
A = sprandn (m,n,d) ;
if (m == 0)
p = [] ;
else
p = randperm (m) ;
end
if (n == 0)
q = [] ;
else
q = randperm (n) ;
end
C = A(p,q) ;
Im = speye (m) ;
In = speye (n) ;
P = Im (p,:) ;
Q = In (:,q) ;
q2 = find (Q) ;
if (any (q ~= q2'))
error ('!')
end
p2 = find (P') ;
if (any (p ~= p2'))
error ('!')
end
E = P*A*Q ;
if (norm (C-E,1) ~= 0)
error ('!')
end
P = sparse (1:m, p, 1) ;
Q = sparse (q, 1:n, 1) ;
E = P*A*Q ;
if (norm (C-E,1) ~= 0)
error ('2!')
end
end
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