function info = trytime(A);

% TRYTIME : time SUPERLU with 3 outputs against Matlab's LU

%

% info = trytime(A);

% normally info is ||P*A*x-L*U*x|| / ||A|| (for a random x);

% but info is at least 10^6 if the factors are not triangular,

% or the permutation isn't a permutation.

% Copyright (c) 1995 by Xerox Corporation.  All rights reserved.

% HELP COPYRIGHT for complete copyright and licensing notice.

n = max(size(A));

info = 0;

format compact

disp('SUPERLU with 3 outputs:');

tic;[L,U,P]=lu(A);t1=toc;

fprintf('LU time = %d seconds.\n',t1);

tic;[l,u,pr]=superlu(A);t2=toc;

fprintf('SUPERLU time = %d seconds.\n',t2);

ratio = t1/t2;

fprintf('Ratio = %d\n',ratio);

if any(any(triu(l,1)))

    disp('L is *NOT* lower triangular.');

    info = info + 10^6;

else

    disp('L is lower triangular.');

end;

if nnz(l) == nnz(l+l)

    disp('L has no explicit zeros.');

else

    disp('L contains explicit zeros.');

    info = info+10^6;

end;

if any(any(tril(u,-1)))

    disp('U is *NOT* upper triangular.');

    info = info + 10^6;

else

    disp('U is upper triangular.');

end;

if nnz(u) == nnz(u+u)

    disp('U has no explicit zeros.');

else

    disp('U contains explicit zeros.');

    info = info+10^6;

end;

if pr == [1:n]

    disp('PROW is the identity permutation.');

elseif isperm(pr)

    disp('PROW is a non-identity permutation.');

else 

    disp('PROW is *NOT* a permutation.');

    info = info + 10^6;

end;

x = rand(n,1);

rnorm = norm(A(pr,:)*x - l*(u*x),inf)/norm(A,inf);

fprintf(1,'||A(PROW,:)*x -  L*U*x||/||A|| = %d\n', rnorm);

info = info + rnorm;

disp(' ');