function info = try4(A,pin);

% TRY4 : test SUPERLU with 4 outputs

%

% info = try4(A,pin);

% normally info is the residual norm; 

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

% or the permutations aren't permutations.

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

% HELP COPYRIGHT for complete copyright and licensing notice.

n = max(size(A));

info = 0;

if nargin == 1

    [l,u,pr,pc] = superlu(A);

elseif nargin == 2

    [l,u,pr,pc] = superlu(A,pin);

else 

    error('requires 1 or 2 inputs');

end;

% DOES NOT WORK IN MATLAB 5, NOT YET KNOW WHY -- XSL 5-25-98

% figure(2); [r,s] = spart2(l); spypart(l,r,s); title('L');

figure(2); spy(l); title('L');

figure(1); spy(u); title('U');

drawnow;

format compact

disp('SUPERLU with 4 outputs:');

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;

if pc == [1:n]

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

elseif isperm(pc)

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

else 

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

    info = info + 10^6;

end;

if pr == pc

    disp('PROW and PCOL are the same.')

else

    disp('PROW and PCOL are different.')

end;

rnorm = norm(A(pr,pc) - l*u,inf);

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

info = info + rnorm;

disp(' ');