function C = and(A,B)%AND Logical AND (&) for sptensors.%%   See also SPTENSOR.%%MATLAB Tensor Toolbox.%Copyright 2007, Sandia Corporation. % This is the MATLAB Tensor Toolbox by Brett Bader and Tamara Kolda. % http://csmr.ca.sandia.gov/~tgkolda/TensorToolbox.% Copyright (2007) 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 tensor_toolbox/LICENSE.txt% $Id: and.m,v 1.4 2007/01/10 01:27:31 bwbader Exp $%% 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.%% Case 1: One argument is a scalarif isscalar(B)    if B == 0                C = sptensor([],[],size(A));    else        C = sptensor(A.subs,true,size(A));    end       return;end% Call back with the arguments reversed.if isscalar(A)    C = and(B,A);    return;end%% Case 2: Both x and y are tensors of some sort% Check that the sizes matchif ~isequal(size(A),size(B))    error('Must be tensors of the same size');endif isa(A,'sptensor') && isa(B,'sptensor')    C = sptensor([A.subs; B.subs], [A.vals; B.vals], size(A), ...        @(x) length(x) == 2);    return;endif isa(B,'tensor')    BB = sptensor(A.subs,B(A.subs),size(A));    C = and(A,BB);    return;    end%% Otherwiseerror('The arguments must be two sptensors or an sptensor and a scalar.');