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function test8
%TEST8 test cs_cholsol, cs_lusol
%
% Example:
% test8
% See also: testall
% CXSparse, Copyright (c) 2006-2022, Timothy A. Davis. All Rights Reserved.
% SPDX-License-Identifier: LGPL-2.1+
index = ssget ;
[ignore f] = sort (max (index.nrows, index.ncols)) ;
f = f (1:100) ;
% f = f(1)
for i = f
Prob = ssget (i) ;
disp (Prob) ;
A = Prob.A ;
[m n] = size (A) ;
if (m ~= n)
continue
end
for cmplex = 0:double(~ispc)
if (cmplex)
A = A + 0.1i * (sprand (tril (A,-1) + triu (A,1))) ;
end
spd = 0 ;
if (m == n)
if (nnz (A-A') == 0)
try
p = amd (A) ;
catch
p = symamd (A) ;
end
[R,p] = chol (A (p,p)) ;
spd = (p == 0) ;
end
end
if (spd)
C = A ;
else
C = A*A' + n*speye (n) ;
try
p = amd (C) ;
catch
p = symamd (C) ;
end
try
R = chol (C (p,p)) ; %#ok
catch
continue
end
end
b = rand (n,1) ;
x1 = C\b ;
x2 = cs_cholsol (C,b) ;
r1 = norm (C*x1-b,1) / norm (C,1) ;
r2 = norm (C*x2-b,1) / norm (C,1) ;
err = abs (r1-r2) ;
fprintf ('err %g\n', err) ;
if (err > 1e-10)
error ('!') ;
end
x2 = cs_lusol (C,b, 1, 0.001) ;
r2 = norm (C*x2-b,1) / norm (C,1) ;
err = abs (r1-r2) ;
fprintf ('err %g (lu with amd(A+A'')\n', err) ;
if (err > 1e-10)
error ('!') ;
end
if (m ~= n)
continue ;
end
x1 = A\b ;
r1 = norm (A*x1-b,1) / norm (A,1) ;
if (r1 < 1e-6)
x2 = cs_lusol (A,b) ;
r2 = norm (A*x2-b,1) / norm (A,1) ;
fprintf ('lu resid %g %g\n', r1, r2) ;
end
end
end
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