function z = gt(x,y)
%GT Greater than for sptensors.
%
%   See also SPTENSOR.
%
%MATLAB Tensor Toolbox.
%Copyright 2012, Sandia Corporation.

% This is the MATLAB Tensor Toolbox by T. Kolda, B. Bader, and others.
% http://www.sandia.gov/~tgkolda/TensorToolbox.
% Copyright (2012) Sandia Corporation. Under the terms of Contract
% DE-AC04-94AL85000, there is a non-exclusive license for use of this
% work by or on behalf of the U.S. Government. Export of this data may
% require a license from the United States Government.
% The full license terms can be found in the file LICENSE.txt


%% Observations for sparse matrix case.
% The result of a > 5 is sparse.
% The result of a > 0 is sparse.
% The result of a > full(a) is sparse.
% The result of a > zeros(a) is sparse.

%% Case 1: One argument is a scalar
if isscalar(y)
    subs1 = x.subs((x.vals > y),:);
    if y < 0
        subs2 = setdiff(allsubs(x),x.subs,'rows');
    else
        subs2 = [];
    end
    z = sptensor([subs1;subs2],true,size(x));
    return;
end

% Call back with the arguments reversed.
if isscalar(x)
    z = lt(y,x);
    return;
end

%% Case 2: Both x and y are tensors of some sort
% Check that the sizes match
if ~isequal(x.size,y.size)
    error('Size mismatch');
end

% Case 2a: Two sparse tensors
if isa(x,'sptensor') && isa(y,'sptensor')
    z = lt(y,x);
    return;
end

% Case 2b: One dense tensor
if isa(y,'tensor')

    % x zero and y < 0
    subs1 = find(y < 0);
    if ~isempty(subs1)
        subs1 = setdiff(subs1,x.subs,'rows');
    end
    
    % x and y nonzero
    subs2 = x.subs(x.vals > y(x.subs,'extract'),:);
    
    % assemble
    z = sptensor([subs1;subs2],true,size(x));
    
    return;
    
end

%% Otherwise
error('The arguments must be two sptensors or an sptensor and a scalar.');
