matbox.de - Matlab

Matlab - trainLaplaceExpand

Laplace Expansion Trainer

A fellow student needed to train the Laplace expansion. This Matlab-script generates a configurable count of sparse matrices with configurable dimension.
Checking the results is made easy by the automatically generated determinants.

Use

help trainLaplaceExpand

to get more help. Or use

[M D]=trainLaplaceExpand(40,4);

to generate 40 sparse matrices with dimension 4 and store them in M. The determinants are stored in the workspace variable D. ( download this example)

Code

download

% train LaplaceExpansion (calculating determinant of sparse matrices)
%
% [M D] = trainLaplaceExpand(numMatrices, dim) generates a 3-dimensional
% matrix M and vector D with the corresponding determinants
%    numMatrices    count of sparse matrices to generate
%    dim            dimension of sparse matrices
%
% (c)2010 by Torsten Reuschel, E-Mail: matlabhelp@fuesika.de
%
% 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 3 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, see <http://www.gnu.org/licenses/>.

function [M D] = trainLaplaceExpand(numMatrices, dim)
    fprintf('Generating %1.f matrices...\n', numMatrices);

    %initialize memory
    M = zeros(dim,dim,numMatrices);
    D = zeros(numMatrices,1);
    
    %generate matrices and calculate determinants
    for i = 1:numMatrices,
        M(:,:,i) = makeSparse(dim);
        D(i) = det(M(:,:,i));
    end
    
    function ma = makeSparse(dim)
        ma = round(sprand(dim,dim,2)*5);
    end
end

matbox.de / Matlab

Matlab - trainLaplaceExpand

Laplace Expansion Trainer

Code