repertory demo quickstart

misc/demo/Quick_start/quick_start.m

+%% Description quick_start
+%
+%  This demo shows that a Faust is handled as matlab builtin matrix,
+% presenting  all the function that are overloaded for Faust class 
+% (size,mtimes,transpose...)
+% and ends with a little time comparison to illustrate 
+% the speed-up of using a Faust for multiplication. 
+%
+% For more information on the FAuST Project, please visit the website of 
+% the project :  <http://faust.gforge.inria.fr>
+%
+%% License:
+% Copyright (2016):	Nicolas Bellot, Adrien Leman, Thomas Gautrais, Luc Le Magoarou, Remi Gribonval
+%			INRIA Rennes, FRANCE
+%			http://www.inria.fr/
+%
+% The FAuST Toolbox is distributed under the terms of the GNU Affero 
+% General Public License.
+% This program is free software: you can redistribute it and/or modify
+% it under the terms of the GNU Affero General Public License as published 
+% by the Free Software Foundation.
+%
+% 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 Affero General Public License for more details.
+%
+% You should have received a copy of the GNU Affero General Public License
+% along with this program.  If not, see <http://www.gnu.org/licenses/>.
+%
+%% Contacts:
+%   Nicolas Bellot	: nicolas.bellot@inria.fr
+%   Adrien Leman	: adrien.leman@inria.fr
+%   Thomas Gautrais	: thomas.gautrais@inria.fr
+%	Luc Le Magoarou	: luc.le-magoarou@inria.fr
+%	Remi Gribonval	: remi.gribonval@inria.fr
+%
+%% References:
+% [1]	Le Magoarou L. and Gribonval R., "Flexible multi-layer sparse 
+%	approximations of matrices and applications", Journal of Selected 
+%	Topics in Signal Processing, 2016.
+%	<https://hal.archives-ouvertes.fr/hal-01167948v1>
+%
+%%
+
+
+% loading a Faust A from saved-one 
+A=Faust('faust_quick_start.mat');
+
+
+ % get the size of the faust
+ [dim1,dim2] = size(A);
+
+ %  transpose a faust  
+ A_trans = A'; 		 
+ 
+ % multiplication by A
+ x1 = rand(dim2,1);
+ y1 = A*x1;  
+ 
+ % multiplication by A'
+ x2 = rand(dim1,5);
+ y2 = A'*x2;
+
+
+ % get the 2-norm (spectral norm) of the faust A
+ norm_A = norm(A); % equivalent to norm(A,2);
+ 
+% convert Faust to full matrix
+A_full=full(A);
+ 
+ 
+ % get the coefficient i,j and slicing for reading purpose
+ coeff=A(3,4);
+ col_2=A(:,2);
+ submatrix_A=A(3:5,2:3);
+ submatrix_A=A(2:end,3:end-1);
+ % Warning :  A(i,j)=3 will not modify A, writing is not allowed
+
+ % get the number of non-zeros coefficient
+ nz = nnz(A);
+ 
+ 
+ %% speed-up multiplication
+nb_mult=100;
+time_full=0;
+time_faust=0;
+
+for i=1:nb_mult
+   tic
+      y=A_full*x1;
+   time_full=time_full+toc;
+   
+   tic
+      y=A*x1;
+   time_faust=time_faust+toc;   
+end
+
+disp('multiplication SPEED-UP using Faust');
+disp(['Faust is ' num2str(time_full/time_faust) ' faster than a full matrix']);