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function test16
%TEST16 test cs_amd
%
% Example:
% test16
% See also: testall
% Copyright 2006-2007, Timothy A. Davis.
% http://www.cise.ufl.edu/research/sparse
rand ('state', 0) ;
randn ('state', 0) ;
clf
index = UFget ;
[ignore f] = sort (max (index.nrows, index.ncols)) ;
f = f (1:200) ;
skip = 811 ;
% f = 719
for i = f
if (any (i == skip))
continue
end
Prob = UFget (i) ;
A = spones (Prob.A) ;
Aorig = A ;
[m n] = size (A) ;
if (m < n)
A = A' ;
end
[m n] = size (A) ;
if (m ~= n)
A = A'*A ;
end
fprintf ('n %4d nz %d\n', n, nnz (A)) ;
try
p0 = amd (A) ;
catch
p0 = symamd (A) ;
end
fprintf ('symmetric case:\n') ;
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 (2,3,1) ; spy (C)
subplot (2,3,2) ; spy (C (p0,p0)) ; title ('amd') ;
subplot (2,3,3) ; spy (C (p1,p1)) ; title ('csamd') ;
drawnow
if (lnz0 ~= lnz1)
fprintf ('----------------- lnz %d %d %9.4f\n', ...
lnz0, lnz1, 100*(lnz0-lnz1)/max([1 lnz0])) ;
end
if (1)
p0 = colamd (Aorig) ;
[m n] = size (Aorig) ;
fprintf ('m %d n %d\n', m, n) ;
fprintf ('A''A case, no dense rows (for QR):\n') ;
p1 = cs_amd (Aorig, 3) ;
if (any (sort (p1) ~= 1:n))
error ('not perm!') ;
end
subplot (2,3,4) ; spy (Aorig)
subplot (2,3,5) ; spy (Aorig (:,p0)) ; title ('colamd') ;
subplot (2,3,6) ; spy (Aorig (:,p1)) ; title ('cs amd(A''A)') ;
lnz0 = sum (symbfact (Aorig (:,p0), 'col')) ;
lnz1 = sum (symbfact (Aorig (:,p1), 'col')) ;
fprintf (' A''A: %7d %7d %9.4f\n', ...
lnz0, lnz1, 100*(lnz0-lnz1)/max([1 lnz0])) ;
drawnow
% pause
end
end
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