Mercurial > hg > smallbox
view solvers/SMALL_ompGabor/omp2Gabor.m @ 243:1fbd28dfb99e unlocbox
setup file
author | bmailhe |
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date | Wed, 29 Aug 2012 10:39:14 +0100 |
parents | 31d2864dfdd4 |
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function gamma = omp2Gabor(varargin) %% omp2Gabor Error-constrained Orthogonal Matching Pursuit. % % This file is part of SMALLbox [2] and it is adaptation of Ron % Rubenstein omp solver [1] for Gabor dictionary as defined in % Audio Inpainting by Adler et al [3]. The dictionary is presented as % DCT+DST and solver pics two atoms per iteration (given the frequency one % from DCT and one from DST). For more information look in [3]. % % GAMMA = OMP2(D,X,G,EPSILON) solves the optimization problem % % min |GAMMA|_0 s.t. |X - D*GAMMA|_2 <= EPSILON % gamma % % for each of the signals in X, using Batch Orthogonal Matching Pursuit. % Here, D is a dictionary with normalized columns, X is a matrix % containing column signals, EPSILON is the error target for each signal, % and G is the Gramm matrix D'*D. The output GAMMA is a matrix containing % the sparse representations as its columns. % % GAMMA = OMP2(D,X,[],EPSILON) performs the same operation, but without % the matrix G, using OMP-Cholesky. This call produces the same output as % Batch-OMP, but is significantly slower. Using this syntax is only % recommended when available memory is too small to store G. % % GAMMA = OMP2(DtX,XtX,G,EPSILON) is the fastest implementation of OMP2, % but also requires the most memory. Here, DtX stores the projections % D'*X, and XtX is a row vector containing the squared norms of the % signals, sum(X.*X). In this case Batch-OMP is used, but without having % to compute D'*X and XtX in advance, which slightly improves runtime. % Note that in general, the call % % GAMMA = OMP2(D'*X, sum(X.*X), G, EPSILON); % % will be faster than the call % % GAMMA = OMP2(D,X,G,EPSILON); % % due to optimized matrix multiplications in Matlab. However, when the % entire matrix D'*X cannot be stored in memory, one of the other two % versions can be used. Both compute D'*X for just one signal at a time, % and thus require much less memory. % % GAMMA = OMP2(...,PARAM1,VAL1,PARAM2,VAL2,...) specifies additional % parameters for OMP2. Available parameters are: % % 'gammamode' - Specifies the representation mode for GAMMA. Can be % either 'full' or 'sparse', corresponding to a full or % sparse matrix, respectively. By default, GAMMA is % returned as a sparse matrix. % 'maxatoms' - Limits the number of atoms in the representation of each % signal. If specified, the number of atoms in each % representation does not exceed this number, even if the % error target is not met. Specifying maxatoms<0 implies % no limit (default). % 'messages' - Specifies whether progress messages should be displayed. % When positive, this is the number of seconds between % status prints. When negative, indicates that no messages % should be displayed (this is the default). % 'checkdict' - Specifies whether dictionary normalization should be % verified. When set to 'on' (default) the dictionary % atoms are verified to be of unit L2-norm. Setting this % parameter to 'off' disables verification and accelerates % function performance. Note that an unnormalized % dictionary will produce invalid results. % 'profile' - Can be either 'on' or 'off'. When 'on', profiling % information is displayed at the end of the funciton % execution. % % % Summary of OMP2 versions: % % version | speed | memory % ------------------------------------------------------------- % OMP2(DtX,XtX,G,EPSILON) | very fast | very large % OMP2(D,X,G,EPSILON) | fast | moderate % OMP2(D,X,[],EPSILON) | very slow | small % ------------------------------------------------------------- % % % References: % [1] M. Elad, R. Rubinstein, and M. Zibulevsky, "Efficient Implementation % of the K-SVD Algorithm using Batch Orthogonal Matching Pursuit", % Technical Report - CS, Technion, April 2008. % % See also OMP. % Ron Rubinstein % Computer Science Department % Technion, Haifa 32000 Israel % ronrubin@cs % % April 2009 % % Centre for Digital Music, Queen Mary, University of London. % This file copyright 2011 Ivan Damnjanovic. % % 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. See the file % COPYING included with this distribution for more information. %% % default options sparse_gamma = 1; msgdelta = -1; maxatoms = -1; checkdict = 1; profile = 0; % determine number of parameters paramnum = 1; while (paramnum<=nargin && ~ischar(varargin{paramnum})) paramnum = paramnum+1; end paramnum = paramnum-1; % parse options for i = paramnum+1:2:length(varargin) paramname = varargin{i}; paramval = varargin{i+1}; switch lower(paramname) case 'gammamode' if (strcmpi(paramval,'sparse')) sparse_gamma = 1; elseif (strcmpi(paramval,'full')) sparse_gamma = 0; else error('Invalid GAMMA mode'); end case 'maxatoms' maxatoms = paramval; case 'messages' msgdelta = paramval; case 'checkdict' if (strcmpi(paramval,'on')) checkdict = 1; elseif (strcmpi(paramval,'off')) checkdict = 0; else error('Invalid checkdict option'); end case 'profile' if (strcmpi(paramval,'on')) profile = 1; elseif (strcmpi(paramval,'off')) profile = 0; else error('Invalid profile mode'); end otherwise error(['Unknown option: ' paramname]); end end % determine call type if (paramnum==4) n1 = size(varargin{1},1); n2 = size(varargin{2},1); n3 = size(varargin{3},1); if ( (n1>1 && n2==1) || (n1==1 && n2==1 && n3==1) ) % DtX,XtX,G,EPSILON DtX = varargin{1}; XtX = varargin{2}; G = varargin{3}; epsilon = varargin{4}; D = []; X = []; else % D,X,G,EPSILON D = varargin{1}; X = varargin{2}; G = varargin{3}; epsilon = varargin{4}; DtX = []; XtX = []; end else error('Invalid number of parameters'); end G=[]; % verify dictionary normalization if (checkdict) if (isempty(G)) atomnorms = sum(D.*D); else atomnorms = diag(G); end if (any(abs(atomnorms-1) > 1e-2)) error('Dictionary columns must be normalized to unit length'); end end % omp gamma = omp2mexGabor(D,X,DtX,XtX,G,epsilon,sparse_gamma,msgdelta,maxatoms,profile);