function test8
%TEST8 test cs_cholsol, cs_lusol
%
% Example:
%   test8
% See also: testall

%   Copyright 2006-2007, Timothy A. Davis.
%   http://www.cise.ufl.edu/research/sparse

index = UFget ;
[ignore f] = sort (max (index.nrows, index.ncols)) ;
f = f (1:100) ;

% f = f(1)

for i = f
    Prob = UFget (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
