function sparsity=spars(x)%Returns the sparsity of the matrix/vector x. It works for sparse and dense%storage, too.% This file is part of SeDuMi 1.1 by Imre Polik and Oleksandr Romanko% Copyright (C) 2005 McMaster University, Hamilton, CANADA  (since 1.1)%% Copyright (C) 2001 Jos F. Sturm (up to 1.05R5)%   Dept. Econometrics & O.R., Tilburg University, the Netherlands.%   Supported by the Netherlands Organization for Scientific Research (NWO).%% Affiliation SeDuMi 1.03 and 1.04Beta (2000):%   Dept. Quantitative Economics, Maastricht University, the Netherlands.%% Affiliations up to SeDuMi 1.02 (AUG1998):%   CRL, McMaster University, Canada.%   Supported by the Netherlands Organization for Scientific Research (NWO).%% This program is free software; you can redistribute it and/or modify% it under the terms of the GNU General Public License as published by% the Free Software Foundation; either version 2 of the License, or% (at your option) any later version.%% This program is distributed in the hope that it will be useful,% but WITHOUT ANY WARRANTY; without even the implied warranty of% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the% GNU General Public License for more details.%% You should have received a copy of the GNU General Public License% along with this program; if not, write to the Free Software% Foundation, Inc.,  51 Franklin Street, Fifth Floor, Boston, MA% 02110-1301, USAif ~isempty(x)    sparsity=nnz(x)/prod(size(x));else    sparsity=0;end