1function [CC]=train_sc(D,classlabel,MODE,W)
2% Train a (statistical) classifier
3%
4%  CC = train_sc(D,classlabel)
5%  CC = train_sc(D,classlabel,MODE)
6%  CC = train_sc(D,classlabel,MODE, W)
7%	weighting D(k,:) with weight W(k) (not all classifiers supported weighting)
8%
9% CC contains the model parameters of a classifier which can be applied
10%   to test data using test_sc.
11%   R = test_sc(CC,D,...)
12%
13%   D		training samples (each row is a sample, each column is a feature)
14%   classlabel	labels of each sample, must have the same number of rows as D.
15% 		Two different encodings are supported:
16%		{-1,1}-encoding (multiple classes with separate columns for each class) or
17%		1..M encoding.
18% 		So [1;2;3;1;4] is equivalent to
19%			[+1,-1,-1,-1;
20%			[-1,+1,-1,-1;
21%			[-1,-1,+1,-1;
22%			[+1,-1,-1,-1]
23%			[-1,-1,-1,+1]
24%		Note, samples with classlabel=0 are ignored.
25%
26%  The following classifier types are supported MODE.TYPE
27%    'MDA'      mahalanobis distance based classifier [1]
28%    'MD2'      mahalanobis distance based classifier [1]
29%    'MD3'      mahalanobis distance based classifier [1]
30%    'GRB'      Gaussian radial basis function     [1]
31%    'QDA'      quadratic discriminant analysis    [1]
32%    'LD2'      linear discriminant analysis (see LDBC2) [1]
33%		MODE.hyperparameter.gamma: regularization parameter [default 0]
34%    'LD3', 'FDA', 'LDA', 'FLDA'
35%               linear discriminant analysis (see LDBC3) [1]
36%		MODE.hyperparameter.gamma: regularization parameter [default 0]
37%    'LD4'      linear discriminant analysis (see LDBC4) [1]
38%		MODE.hyperparameter.gamma: regularization parameter [default 0]
39%    'LD5'      another LDA (motivated by CSP)
40%		MODE.hyperparameter.gamma: regularization parameter [default 0]
41%    'RDA'      regularized discriminant analysis [7]
42%		MODE.hyperparameter.gamma: regularization parameter
43%		MODE.hyperparameter.lambda =
44%		gamma = 0, lambda = 0 : MDA
45%		gamma = 0, lambda = 1 : LDA [default]
46%		Hint: hyperparameter are used only in test_sc.m, testing different
47%		the hyperparameters do not need repetitive calls to train_sc,
48%		it is sufficient to modify CC.hyperparameter before calling test_sc.
49%    'GDBC'     general distance based classifier  [1]
50%    ''         statistical classifier, requires Mode argument in TEST_SC
51%    '###/DELETION'  if the data contains missing values (encoded as NaNs),
52%		a row-wise or column-wise deletion (depending on which method
53%		removes less data values) is applied;
54%    '###/GSVD'	GSVD and statistical classifier [2,3],
55%    '###/sparse'  sparse  [5]
56%		'###' must be 'LDA' or any other classifier
57%    'PLS'	(linear) partial least squares regression
58%    'REG'      regression analysis;
59%    'WienerHopf'	Wiener-Hopf equation
60%    'NBC'	Naive Bayesian Classifier [6]
61%    'aNBC'	Augmented Naive Bayesian Classifier [6]
62%    'NBPW'	Naive Bayesian Parzen Window [9]
63%
64%    'PLA'	Perceptron Learning Algorithm [11]
65%		MODE.hyperparameter.alpha = alpha [default: 1]
66%		 w = w + alpha * e'*x
67%    'LMS', 'AdaLine'  Least mean squares, adaptive line element, Widrow-Hoff, delta rule
68%		MODE.hyperparameter.alpha = alpha [default: 1]
69%    'Winnow2'  Winnow2 algorithm [12]
70%
71%    'PSVM'	Proximal SVM [8]
72%		MODE.hyperparameter.nu  (default: 1.0)
73%    'LPM'      Linear Programming Machine
74%                 uses and requires train_LPM of the iLog CPLEX optimizer
75%		MODE.hyperparameter.c_value =
76%    'CSP'	CommonSpatialPattern is very experimental and just a hack
77%		uses a smoothing window of 50 samples.
78%    'SVM','SVM1r'  support vector machines, one-vs-rest
79%		MODE.hyperparameter.c_value =
80%    'SVM11'    support vector machines, one-vs-one + voting
81%		MODE.hyperparameter.c_value =
82%    'RBF'      Support Vector Machines with RBF Kernel
83%		MODE.hyperparameter.c_value =
84%		MODE.hyperparameter.gamma =
85%    'SVM:LIB'    libSVM [default SVM algorithm)
86%    'SVM:bioinfo' uses and requires svmtrain from the bioinfo toolbox
87%    'SVM:OSU'   uses and requires mexSVMTrain from the OSU-SVM toolbox
88%    'SVM:LOO'   uses and requires svcm_train from the LOO-SVM toolbox
89%    'SVM:Gunn'  uses and requires svc-functios from the Gunn-SVM toolbox
90%    'SVM:KM'    uses and requires svmclass-function from the KM-SVM toolbox
91%    'SVM:LINz'  LibLinear [10] (requires train.mex from LibLinear somewhere in the path)
92%            z=0 (default) LibLinear with -- L2-regularized logistic regression
93%            z=1 LibLinear with -- L2-loss support vector machines (dual)
94%            z=2 LibLinear with -- L2-loss support vector machines (primal)
95%            z=3 LibLinear with -- L1-loss support vector machines (dual)
96%    'SVM:LIN4'  LibLinear with -- multi-class support vector machines by Crammer and Singer
97%    'DT'	decision tree - not implemented yet.
98%
99% {'REG','MDA','MD2','QDA','QDA2','LD2','LD3','LD4','LD5','LD6','NBC','aNBC','WienerHopf','LDA/GSVD','MDA/GSVD', 'LDA/sparse','MDA/sparse', 'PLA', 'LMS','LDA/DELETION','MDA/DELETION','NBC/DELETION','RDA/DELETION','REG/DELETION','RDA','GDBC','SVM','RBF','PSVM','SVM11','SVM:LIN4','SVM:LIN0','SVM:LIN1','SVM:LIN2','SVM:LIN3','WINNOW', 'DT'};
100%
101% CC contains the model parameters of a classifier. Some time ago,
102% CC was a statistical classifier containing the mean
103% and the covariance of the data of each class (encoded in the
104%  so-called "extended covariance matrices". Nowadays, also other
105% classifiers are supported.
106%
107% see also: TEST_SC, COVM, ROW_COL_DELETION
108%
109% References:
110% [1] R. Duda, P. Hart, and D. Stork, Pattern Classification, second ed.
111%       John Wiley & Sons, 2001.
112% [2] Peg Howland and Haesun Park,
113%       Generalizing Discriminant Analysis Using the Generalized Singular Value Decomposition
114%       IEEE Transactions on Pattern Analysis and Machine Intelligence, 26(8), 2004.
115%       dx.doi.org/10.1109/TPAMI.2004.46
116% [3] http://www-static.cc.gatech.edu/~kihwan23/face_recog_gsvd.htm
117% [4] Jieping Ye, Ravi Janardan, Cheong Hee Park, Haesun Park
118%       A new optimization criterion for generalized discriminant analysis on undersampled problems.
119%       The Third IEEE International Conference on Data Mining, Melbourne, Florida, USA
120%       November 19 - 22, 2003
121% [5] J.D. Tebbens and P. Schlesinger (2006),
122%       Improving Implementation of Linear Discriminant Analysis for the Small Sample Size Problem
123%	Computational Statistics & Data Analysis, vol 52(1): 423-437, 2007
124%       http://www.cs.cas.cz/mweb/download/publi/JdtSchl2006.pdf
125% [6] H. Zhang, The optimality of Naive Bayes,
126%	 http://www.cs.unb.ca/profs/hzhang/publications/FLAIRS04ZhangH.pdf
127% [7] J.H. Friedman. Regularized discriminant analysis.
128%	Journal of the American Statistical Association, 84:165–175, 1989.
129% [8] G. Fung and O.L. Mangasarian, Proximal Support Vector Machine Classifiers, KDD 2001.
130%        Eds. F. Provost and R. Srikant, Proc. KDD-2001: Knowledge Discovery and Data Mining, August 26-29, 2001, San Francisco, CA.
131% 	p. 77-86.
132% [9] Kai Keng Ang, Zhang Yang Chin, Haihong Zhang, Cuntai Guan.
133%	Filter Bank Common Spatial Pattern (FBCSP) in Brain-Computer Interface.
134%	IEEE International Joint Conference on Neural Networks, 2008. IJCNN 2008. (IEEE World Congress on Computational Intelligence).
135%	1-8 June 2008 Page(s):2390 - 2397
136% [10] R.-E. Fan, K.-W. Chang, C.-J. Hsieh, X.-R. Wang, and C.-J. Lin.
137%       LIBLINEAR: A Library for Large Linear Classification, Journal of Machine Learning Research 9(2008), 1871-1874.
138%       Software available at http://www.csie.ntu.edu.tw/~cjlin/liblinear
139% [11] http://en.wikipedia.org/wiki/Perceptron#Learning_algorithm
140% [12] Littlestone, N. (1988)
141%       "Learning Quickly When Irrelevant Attributes Abound: A New Linear-threshold Algorithm"
142%       Machine Learning 285-318(2)
143% 	http://en.wikipedia.org/wiki/Winnow_(algorithm)
144
145%	$Id$
146%	Copyright (C) 2005,2006,2007,2008,2009,2010 by Alois Schloegl <alois.schloegl@gmail.com>
147%       This function is part of the NaN-toolbox
148%       http://pub.ist.ac.at/~schloegl/matlab/NaN/
149
150% This program is free software; you can redistribute it and/or
151% modify it under the terms of the GNU General Public License
152% as published by the Free Software Foundation; either version 3
153% of the  License, or (at your option) any later version.
154%
155% This program is distributed in the hope that it will be useful,
156% but WITHOUT ANY WARRANTY; without even the implied warranty of
157% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
158% GNU General Public License for more details.
159%
160% You should have received a copy of the GNU General Public License
161% along with this program; if not, write to the Free Software
162% Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
163
164        if nargin<2,
165                error('insufficient input arguments\n\tusage: train_sc(D,C,...)\n');
166        end
167        if nargin<3, MODE = 'LDA'; end
168        if nargin<4, W = []; end
169        if ischar(MODE)
170                tmp = MODE;
171                clear MODE;
172                MODE.TYPE = tmp;
173        elseif ~isfield(MODE,'TYPE')
174                MODE.TYPE='';
175        end
176
177        if isfield(MODE,'hyperparameters') && ~isfield(MODE,'hyperparameter'),
178                %% for backwards compatibility, this might become obsolete
179                warning('MODE.hyperparameters are used, You should use MODE.hyperparameter instead!!!');
180                MODE.hyperparameter = MODE.hyperparameters;
181        end
182
183        sz = size(D);
184        if sz(1)~=size(classlabel,1),
185                error('length of data and classlabel does not fit');
186        end
187
188        % remove all NaN's
189        if 1,
190                % several classifier can deal with NaN's, there is no need to remove them.
191        elseif isempty(W)
192                %% TODO: some classifiers can deal with NaN's in D. Test whether this can be relaxed.
193                %ix = any(isnan([classlabel]),2);
194                ix = any(isnan([D,classlabel]),2);
195                D(ix,:) = [];
196                classlabel(ix,:)=[];
197                W = [];
198        else
199                %ix = any(isnan([classlabel]),2);
200                ix = any(isnan([D,classlabel]),2);
201                D(ix,:)=[];
202                classlabel(ix,:)=[];
203                W(ix,:)=[];
204                warning('support for weighting of samples is still experimental');
205        end
206
207        sz = size(D);
208        if sz(1)~=length(classlabel),
209                error('length of data and classlabel does not fit');
210        end
211        if ~isfield(MODE,'hyperparameter')
212                MODE.hyperparameter = [];
213        end
214
215        if 0,
216                ;
217        elseif ~isempty(strfind(lower(MODE.TYPE),'/delet'))
218                POS1 = find(MODE.TYPE=='/');
219                [rix,cix] = row_col_deletion(D);
220                if ~isempty(W), W=W(rix); end
221                CC   = train_sc(D(rix,cix),classlabel(rix,:),MODE.TYPE(1:POS1(1)-1),W);
222                CC.G = sparse(cix, 1:length(cix), 1, size(D,2), length(cix));
223                if isfield(CC,'weights')
224                        W = [CC.weights(1,:); CC.weights(2:end,:)];
225                        CC.weights = sparse(size(D,2)+1, size(W,2));
226                        CC.weights([1,cix+1],:) = W;
227                        CC.datatype = ['classifier:statistical:',lower(MODE.TYPE)];
228                else
229                        CC.datatype = [CC.datatype,'/delet'];
230                end
231
232        elseif ~isempty(strfind(lower(MODE.TYPE),'nbpw'))
233                error('NBPW not implemented yet')
234                %%%% Naive Bayesian Parzen Window Classifier.
235                [classlabel,CC.Labels] = CL1M(classlabel);
236                for k = 1:length(CC.Labels),
237                        [d,CC.MEAN(k,:)] = center(D(classlabel==CC.Labels(k),:),1);
238                        [CC.VAR(k,:),CC.N(k,:)] = sumskipnan(d.^2,1);
239                        h2_opt = (4./(3*CC.N(k,:))).^(2/5).*CC.VAR(k,:);
240                        %%% TODO
241                end
242
243
244        elseif ~isempty(strfind(lower(MODE.TYPE),'nbc'))
245                %%%% Naive Bayesian Classifier
246                if ~isempty(strfind(lower(MODE.TYPE),'anbc'))
247                        %%%% Augmented Naive Bayesian classifier.
248                        [CC.V,L] = eig(covm(D,'M',W));
249                        D = D*CC.V;
250                else
251                        CC.V = eye(size(D,2));
252                end
253                [classlabel,CC.Labels] = CL1M(classlabel);
254                for k = 1:length(CC.Labels),
255                        ix = classlabel==CC.Labels(k);
256                        %% [d,CC.MEAN(k,:)] = center(D(ix,:),1);
257                        if ~isempty(W)
258                                [s,n] = sumskipnan(D(ix,:),1,W(ix));
259                                CC.MEAN(k,:) = s./n;
260                                d = D(ix,:) - CC.MEAN(repmat(k,sum(ix),1),:);
261                                [CC.VAR(k,:),CC.N(k,:)] = sumskipnan(d.^2,1,W(ix));
262                        else
263                                [s,n] = sumskipnan(D(ix,:),1);
264                                CC.MEAN(k,:) = s./n;
265                                d = D(ix,:) - CC.MEAN(repmat(k,sum(ix),1),:);
266                                [CC.VAR(k,:),CC.N(k,:)] = sumskipnan(d.^2,1);
267                        end
268                end
269                CC.VAR = CC.VAR./max(CC.N-1,0);
270                CC.datatype = ['classifier:',lower(MODE.TYPE)];
271
272
273        elseif ~isempty(strfind(lower(MODE.TYPE),'lpm'))
274                if ~isempty(W)
275                        error('Error TRAIN_SC: Classifier (%s) does not support weighted samples.',MODE.TYPE);
276                end
277                % linear programming machine
278                % CPLEX optimizer: ILOG solver, ilog cplex 6.5 reference manual http://www.ilog.com
279                MODE.TYPE = 'LPM';
280                if ~isfield(MODE.hyperparameter,'c_value')
281                        MODE.hyperparameter.c_value = 1;
282                end
283                [classlabel,CC.Labels] = CL1M(classlabel);
284
285                M = length(CC.Labels);
286                if M==2, M=1; end   % For a 2-class problem, only 1 Discriminant is needed
287                for k = 1:M,
288                        %LPM = train_LPM(D,(classlabel==CC.Labels(k)),'C',MODE.hyperparameter.c_value);
289                        LPM = train_LPM(D',(classlabel'==CC.Labels(k)));
290                        CC.weights(:,k) = [-LPM.b; LPM.w(:)];
291                end
292                CC.hyperparameter.c_value = MODE.hyperparameter.c_value;
293                CC.datatype = ['classifier:',lower(MODE.TYPE)];
294
295
296        elseif ~isempty(strfind(lower(MODE.TYPE),'pla')),
297                % Perceptron Learning Algorithm
298
299                [rix,cix] = row_col_deletion(D);
300                [CL101,CC.Labels] = cl101(classlabel);
301                M = size(CL101,2);
302                weights   = sparse(length(cix)+1,M);
303
304                %ix = randperm(size(D,1));      %% randomize samples ???
305                if ~isfield(MODE.hyperparameter,'alpha')
306                        if isfield(MODE.hyperparameter,'alpha')
307                                alpha = MODE.hyperparameter.alpha;
308                        else
309                                alpha = 1;
310                        end
311                        for k = rix(:)',
312                                %e = ((classlabel(k)==(1:M))-.5) - sign([1, D(k,cix)] * weights)/2;
313                                e = CL101(k,:) - sign([1, D(k,cix)] * weights);
314                                weights = weights + alpha * [1,D(k,cix)]' * e ;
315                        end
316
317                else %if ~isempty(W)
318                        if isfield(MODE.hyperparameter,'alpha')
319                                W = W*MODE.hyperparameter.alpha;
320                        end
321                        for k = rix(:)',
322                                %e = ((classlabel(k)==(1:M))-.5) - sign([1, D(k,cix)] * weights)/2;
323                                e = CL101(k,:) - sign([1, D(k,cix)] * weights);
324                                weights = weights + W(k) * [1,D(k,cix)]' * e ;
325                        end
326                end
327                CC.weights  = sparse(size(D,2)+1,M);
328                CC.weights([1,cix+1],:) = weights;
329                CC.datatype = ['classifier:',lower(MODE.TYPE)];
330
331
332        elseif  ~isempty(strfind(lower(MODE.TYPE),'adaline')) || ~isempty(strfind(lower(MODE.TYPE),'lms')),
333                % adaptive linear elemente, least mean squares, delta rule, Widrow-Hoff,
334
335                [rix,cix] = row_col_deletion(D);
336                [CL101,CC.Labels] = cl101(classlabel);
337                M = size(CL101,2);
338                weights  = sparse(length(cix)+1,M);
339
340                %ix = randperm(size(D,1));      %% randomize samples ???
341                if isempty(W)
342                        if isfield(MODE.hyperparameter,'alpha')
343                                alpha = MODE.hyperparameter.alpha;
344                        else
345                                alpha = 1;
346                        end
347                        for k = rix(:)',
348                                %e = (classlabel(k)==(1:M)) - [1, D(k,cix)] * weights;
349                                e = CL101(k,:) - sign([1, D(k,cix)] * weights);
350                                weights = weights + alpha * [1,D(k,cix)]' * e ;
351                        end
352
353                else %if ~isempty(W)
354                        if isfield(MODE.hyperparameter,'alpha')
355                                W = W*MODE.hyperparameter.alpha;
356                        end
357                        for k = rix(:)',
358                                %e = (classlabel(k)==(1:M)) - [1, D(k,cix)] * weights;
359                                e = CL101(k,:) - sign([1, D(k,cix)] * weights);
360                                weights = weights + W(k) * [1,D(k,cix)]' * e ;
361                        end
362                end
363                CC.weights  = sparse(size(D,2)+1,M);
364                CC.weights([1,cix+1],:) = weights;
365                CC.datatype = ['classifier:',lower(MODE.TYPE)];
366
367
368        elseif ~isempty(strfind(lower(MODE.TYPE),'winnow'))
369                % winnow algorithm
370                if ~isempty(W)
371                        error('Classifier (%s) does not support weighted samples.',MODE.TYPE);
372                end
373
374                [rix,cix] = row_col_deletion(D);
375                [CL101,CC.Labels] = cl101(classlabel);
376                M = size(CL101,2);
377                weights  = ones(length(cix),M);
378                theta = size(D,2)/2;
379
380                for k = rix(:)',
381                        e = CL101(k,:) - sign(D(k,cix) * weights - theta);
382                        weights = weights.* 2.^(D(k,cix)' * e);
383                end
384
385                CC.weights = sparse(size(D,2)+1,M);
386                CC.weights(cix+1,:) = weights;
387                CC.datatype = ['classifier:',lower(MODE.TYPE)];
388
389        elseif ~isempty(strfind(lower(MODE.TYPE),'pls')) || ~isempty(strfind(lower(MODE.TYPE),'reg'))
390                % 4th version: support for weighted samples - work well with unequally distributed data:
391                % regression analysis, can handle sparse data, too.
392
393                if nargin<4,
394                        W = [];
395                end
396                [rix, cix] = row_col_deletion(D);
397                wD = [ones(length(rix),1),D(rix,cix)];
398
399                if ~isempty(W)
400                        %% wD = diag(W)*wD
401                        W = W(:);
402                        for k=1:size(wD,2)
403                                wD(:,k) = W(rix).*wD(:,k);
404                        end
405                end
406                [CL101, CC.Labels] = cl101(classlabel(rix,:));
407                M = size(CL101,2);
408                CC.weights = sparse(sz(2)+1,M);
409
410                %[rix, cix] = row_col_deletion(wD);
411                [q,r] = qr(wD,0);
412
413                if isempty(W)
414                        CC.weights([1,cix+1],:) = r\(q'*CL101);
415                else
416                        CC.weights([1,cix+1],:) = r\(q'*(W(rix,ones(1,M)).*CL101));
417                end
418                %for k = 1:M,
419                %       CC.weights(cix,k) = r\(q'*(W.*CL101(rix,k)));
420                %end
421                CC.datatype = ['classifier:statistical:',lower(MODE.TYPE)];
422
423
424        elseif ~isempty(strfind(MODE.TYPE,'WienerHopf'))
425                % Q: equivalent to LDA
426                % equivalent to Regression, except regression can not deal with NaN's
427                [CL101,CC.Labels] = cl101(classlabel);
428                M = size(CL101,2);
429                CC.weights = sparse(size(D,2)+1,M);
430                cc = covm(D,'E',W);
431                %c1 = classlabel(~isnan(classlabel));
432                %c2 = ones(sum(~isnan(classlabel)),M);
433                %for k = 1:M,
434                %       c2(:,k) = c1==CC.Labels(k);
435                %end
436                %CC.weights  = cc\covm([ones(size(c2,1),1),D(~isnan(classlabel),:)],2*real(c2)-1,'M',W);
437                CC.weights  = cc\covm([ones(size(D,1),1),D],CL101,'M',W);
438                CC.datatype = ['classifier:statistical:',lower(MODE.TYPE)];
439
440
441        elseif ~isempty(strfind(lower(MODE.TYPE),'/gsvd'))
442                if ~isempty(W)
443                        error('Classifier (%s) does not support weighted samples.',MODE.TYPE);
444                end
445                % [2] Peg Howland and Haesun Park, 2004
446                %       Generalizing Discriminant Analysis Using the Generalized Singular Value Decomposition
447                %       IEEE Transactions on Pattern Analysis and Machine Intelligence, 26(8), 2004.
448                %       dx.doi.org/10.1109/TPAMI.2004.46
449                % [3] http://www-static.cc.gatech.edu/~kihwan23/face_recog_gsvd.htm
450
451                [classlabel,CC.Labels] = CL1M(classlabel);
452                [rix,cix] = row_col_deletion(D);
453
454                Hw = zeros(length(rix)+length(CC.Labels), length(cix));
455                Hb = [];
456                m0 = mean(D(rix,cix));
457                K = length(CC.Labels);
458                N = zeros(1,K);
459                for k = 1:K,
460                        ix   = find(classlabel(rix)==CC.Labels(k));
461                        N(k) = length(ix);
462                        [Hw(ix,:), mu] = center(D(rix(ix),cix));
463                        %Hb(k,:) = sqrt(N(k))*(mu(k,:)-m0);
464                        Hw(length(rix)+k,:) = sqrt(N(k))*(mu-m0);  % Hb(k,:)
465                end
466                try
467                        [P,R,Q] = svd(Hw,'econ');
468                catch   % needed because SVD(..,'econ') not supported in Matlab 6.x
469                        [P,R,Q] = svd(Hw,0);
470                end
471                t = rank(R);
472
473                clear Hw Hb mu;
474                %[size(D);size(P);size(Q);size(R)]
475                R = R(1:t,1:t);
476                %P = P(1:size(D,1),1:t);
477                %Q = Q(1:t,:);
478                [U,E,W] = svd(P(1:length(rix),1:t),0);
479                %[size(U);size(E);size(W)]
480                clear U E P;
481                %[size(Q);size(R);size(W)]
482
483                %G = Q(1:t,:)'*[R\W'];
484                G = Q(:,1:t)*(R\W');   % this works as well and needs only 'econ'-SVD
485                %G = G(:,1:t);  % not needed
486
487                % do not use this, gives very bad results for Medline database
488                %G = G(:,1:K); this seems to be a typo in [2] and [3].
489                CC = train_sc(D(:,cix)*G,classlabel,MODE.TYPE(1:find(MODE.TYPE=='/')-1));
490                CC.G = sparse(size(D,2),size(G,2));
491                CC.G(cix,:) = G;
492                if isfield(CC,'weights')
493                        CC.weights  = sparse([CC.weights(1,:); CC.G*CC.weights(2:end,:)]);
494                        CC.datatype = ['classifier:statistical:', lower(MODE.TYPE)];
495                else
496                        CC.datatype = [CC.datatype,'/gsvd'];
497                end
498
499
500        elseif ~isempty(strfind(lower(MODE.TYPE),'sparse'))
501                if ~isempty(W)
502                        error('Classifier (%s) does not support weighted samples.',MODE.TYPE);
503                end
504                % [5] J.D. Tebbens and P.Schlesinger (2006),
505                %       Improving Implementation of Linear Discriminant Analysis for the Small Sample Size Problem
506                %       http://www.cs.cas.cz/mweb/download/publi/JdtSchl2006.pdf
507
508                [classlabel,CC.Labels] = CL1M(classlabel);
509                [rix,cix] = row_col_deletion(D);
510
511                warning('sparse LDA is sensitive to linear transformations')
512                M = length(CC.Labels);
513                G  = sparse([],[],[],length(rix),M,length(rix));
514                for k = 1:M,
515                        G(classlabel(rix)==CC.Labels(k),k) = 1;
516                end
517                tol  = 1e-10;
518
519                G    = train_lda_sparse(D(rix,cix),G,1,tol);
520                CC.datatype = 'classifier:slda';
521                POS1 = find(MODE.TYPE=='/');
522                %G = v(:,1:size(G.trafo,2)).*G.trafo;
523                %CC.weights = s * CC.weights(2:end,:) + sparse(1,1:M,CC.weights(1,:),sz(2)+1,M);
524
525                CC = train_sc(D(rix,cix)*G.trafo,classlabel(rix),MODE.TYPE(1:POS1(1)-1));
526                CC.G = sparse(size(D,2),size(G.trafo,2));
527                CC.G(cix,:) = G.trafo;
528                if isfield(CC,'weights')
529                        CC.weights = sparse([CC.weights(1,:); CC.G*CC.weights(2:end,:)]);
530                        CC.datatype = ['classifier:statistical:',lower(MODE.TYPE)];
531                else
532                        CC.datatype = [CC.datatype,'/sparse'];
533                end
534
535        elseif ~isempty(strfind(lower(MODE.TYPE),'rbf'))
536                if ~isempty(W)
537                        error('Classifier (%s) does not support weighted samples.',MODE.TYPE);
538                end
539
540                % Martin Hieden's RBF-SVM
541                if exist('svmpredict_mex','file')==3,
542                        MODE.TYPE = 'SVM:LIB:RBF';
543                else
544                        error('No SVM training algorithm available. Install LibSVM for Matlab.\n');
545                end
546                CC.options = '-t 2 -q';   %use RBF kernel, set C, set gamma
547                if isfield(MODE.hyperparameter,'gamma')
548                        CC.options = sprintf('%s -c %g', CC.options, MODE.hyperparameter.c_value);  % set C
549                end
550                if isfield(MODE.hyperparameter,'c_value')
551                        CC.options = sprintf('%s -g %g', CC.options, MODE.hyperparameter.gamma);  % set C
552                end
553
554                % pre-whitening
555                [D,r,m]=zscore(D,1);
556                CC.prewhite = sparse(2:sz(2)+1,1:sz(2),r,sz(2)+1,sz(2),2*sz(2));
557                CC.prewhite(1,:) = -m.*r;
558
559                [classlabel,CC.Labels] = CL1M(classlabel);
560                CC.model = svmtrain_mex(classlabel, D, CC.options);    % Call the training mex File
561                CC.datatype = ['classifier:',lower(MODE.TYPE)];
562
563
564        elseif ~isempty(strfind(lower(MODE.TYPE),'svm11'))
565                if ~isempty(W)
566                        error('Classifier (%s) does not support weighted samples.',MODE.TYPE);
567                end
568                % 1-versus-1 scheme
569                if ~isfield(MODE.hyperparameter,'c_value')
570                        MODE.hyperparameter.c_value = 1;
571                end
572
573                CC.options=sprintf('-c %g -t 0 -q',MODE.hyperparameter.c_value);  %use linear kernel, set C
574                CC.hyperparameter.c_value = MODE.hyperparameter.c_value;
575
576                % pre-whitening
577                [D,r,m]=zscore(D,1);
578                CC.prewhite = sparse(2:sz(2)+1,1:sz(2),r,sz(2)+1,sz(2),2*sz(2));
579                CC.prewhite(1,:) = -m.*r;
580
581                [classlabel,CC.Labels] = CL1M(classlabel);
582                CC.model = svmtrain_mex(classlabel, D, CC.options);    % Call the training mex File
583
584                FUN = 'SVM:LIB:1vs1';
585                CC.datatype = ['classifier:',lower(FUN)];
586
587
588        elseif ~isempty(strfind(lower(MODE.TYPE),'psvm'))
589                if ~isempty(W)
590                        %%% error('Classifier (%s) does not support weighted samples.',MODE.TYPE);
591                        warning('Classifier (%s) in combination with weighted samples is not tested.',MODE.TYPE);
592                end
593                if ~isfield(MODE,'hyperparameter')
594                        nu = 1;
595                elseif isfield(MODE.hyperparameter,'nu')
596                        nu = MODE.hyperparameter.nu;
597                else
598                        nu = 1;
599                end
600                [m,n] = size(D);
601                [CL101,CC.Labels] = cl101(classlabel);
602                CC.weights = sparse(n+1,size(CL101,2));
603                M = size(CL101,2);
604                for k = 1:M,
605                        d = sparse(1:m,1:m,CL101(:,k));
606                        H = d * [ones(m,1),D];
607                        %%% r = sum(H,1)';
608                        r = sumskipnan(H,1,W)';
609                        %%% r = (speye(n+1)/nu + H' * H)\r; %solve (I/nu+H’*H)r=H’*e
610                        [HTH, nn] = covm(H,H,'M',W);
611                        r = (speye(n+1)/nu + HTH)\r; %solve (I/nu+H’*H)r=H’*e
612                        u = nu*(1-(H*r));
613                        %%% CC.weights(:,k) = u'*H;
614                        [c,nn] = covm(u,H,'M',W);
615                        CC.weights(:,k) = c';
616                end
617                CC.hyperparameter.nu = nu;
618                CC.datatype = ['classifier:',lower(MODE.TYPE)];
619
620        elseif ~isempty(strfind(lower(MODE.TYPE),'svm:lin4'))
621                if ~isfield(MODE.hyperparameter,'c_value')
622                        MODE.hyperparameter.c_value = 1;
623                end
624
625                [classlabel,CC.Labels] = CL1M(classlabel);
626                M = length(CC.Labels);
627                CC.weights = sparse(size(D,2)+1,M);
628
629                [rix,cix] = row_col_deletion(D);
630
631                % pre-whitening
632                [D,r,m]=zscore(D(rix,cix),1);
633                sz2 = length(cix);
634                s = sparse(2:sz2+1,1:sz2,r,sz2+1,sz2,2*sz2);
635                s(1,:) = -m.*r;
636
637                CC.options = sprintf('-s 4 -B 1 -c %f -q', MODE.hyperparameter.c_value);      % C-SVC, C=1, linear kernel, degree = 1,
638                model = train(W, classlabel, sparse(D), CC.options);    % C-SVC, C=1, linear kernel, degree = 1,
639                weights = model.w([end,1:end-1],:)';
640
641                CC.weights([1,cix+1],:) = s * weights(2:end,:) + sparse(1,1:M,weights(1,:),sz2+1,M); % include pre-whitening transformation
642                CC.weights([1,cix+1],:) = s * CC.weights(cix+1,:) + sparse(1,1:M,CC.weights(1,:),sz2+1,M); % include pre-whitening transformation
643                CC.hyperparameter.c_value = MODE.hyperparameter.c_value;
644                CC.datatype = ['classifier:',lower(MODE.TYPE)];
645
646
647        elseif ~isempty(strfind(lower(MODE.TYPE),'svm'))
648
649                if ~isfield(MODE.hyperparameter,'c_value')
650                        MODE.hyperparameter.c_value = 1;
651                end
652                if any(MODE.TYPE==':'),
653                        % nothing to be done
654                elseif exist('train','file')==3,
655                        MODE.TYPE = 'SVM:LIN';        %% liblinear
656                elseif exist('svmtrain_mex','file')==3,
657                        MODE.TYPE = 'SVM:LIB';
658                elseif (exist('svmtrain','file')==3),
659                        MODE.TYPE = 'SVM:LIB';
660                        fprintf(1,'You need to rename %s to svmtrain_mex.mex !! \n Press any key to continue !!!\n',which('svmtrain.mex'));
661                elseif exist('svmtrain','file')==2,
662                        MODE.TYPE = 'SVM:bioinfo';
663                elseif exist('mexSVMTrain','file')==3,
664                        MODE.TYPE = 'SVM:OSU';
665                elseif exist('svcm_train','file')==2,
666                        MODE.TYPE = 'SVM:LOO';
667                elseif exist('svmclass','file')==2,
668                        MODE.TYPE = 'SVM:KM';
669                elseif exist('svc','file')==2,
670                        MODE.TYPE = 'SVM:Gunn';
671                else
672                        error('No SVM training algorithm available. Install OSV-SVM, or LOO-SVM, or libSVM for Matlab.\n');
673                end
674
675                %%CC = train_svm(D,classlabel,MODE);
676                [CL101,CC.Labels] = cl101(classlabel);
677                M = size(CL101,2);
678                [rix,cix] = row_col_deletion(D);
679                CC.weights = sparse(sz(2)+1, M);
680
681                % pre-whitening
682                [D,r,m]=zscore(D(rix,cix),1);
683                sz2 = length(cix);
684                s = sparse(2:sz2+1,1:sz2,r,sz2+1,sz2,2*sz2);
685                s(1,:) = -m.*r;
686
687                for k = 1:M,
688                        cl = CL101(rix,k);
689                        if strncmp(MODE.TYPE, 'SVM:LIN',7);
690                                if isfield(MODE,'options')
691                                        CC.options = MODE.options;
692                                else
693                                        t = 0;
694                                        if length(MODE.TYPE)>7, t=MODE.TYPE(8)-'0'; end
695                                        if (t<0 || t>6) t=0; end
696                                        CC.options = sprintf('-s %i -B 1 -c %f -q',t, MODE.hyperparameter.c_value);      % C-SVC, C=1, linear kernel, degree = 1,
697                                end
698                                model = train(W, cl, sparse(D), CC.options);    % C-SVC, C=1, linear kernel, degree = 1,
699                                w = -model.w';
700                                Bias = -model.bias;
701                                w = -model.w(:,1:end-1)';
702                                Bias = -model.w(:,end)';
703
704                        elseif strcmp(MODE.TYPE, 'SVM:LIB');    %% tested with libsvm-mat-2.9-1
705                                if isfield(MODE,'options')
706                                        CC.options = MODE.options;
707                                else
708                                        CC.options = sprintf('-s 0 -c %f -t 0 -d 1 -q', MODE.hyperparameter.c_value);      % C-SVC, C=1, linear kernel, degree = 1,
709                                end
710                                model = svmtrain_mex(cl, D, CC.options);    % C-SVC, C=1, linear kernel, degree = 1,
711                                w = cl(1) * model.SVs' * model.sv_coef;  %Calculate decision hyperplane weight vector
712                                % ensure correct sign of weight vector and Bias according to class label
713                                Bias = model.rho * cl(1);
714
715                        elseif strcmp(MODE.TYPE, 'SVM:bioinfo');
716                                % SVM classifier from bioinformatics toolbox.
717                                % Settings suggested by Ian Daly, 2011-06-06
718                                options = optimset('Display','iter','maxiter',20000, 'largescale','off');
719                                CC.SVMstruct = svmtrain(D, cl, 'AUTOSCALE', 0, 'quadprog_opts', options, 'Method', 'LS', 'kernel_function', 'polynomial');
720                                Bias = -CC.SVMstruct.Bias;
721                                w = -CC.SVMstruct.Alpha'*CC.SVMstruct.SupportVectors;
722
723                        elseif strcmp(MODE.TYPE, 'SVM:OSU');
724                                [AlphaY, SVs, Bias] = mexSVMTrain(D', cl', [0 1 1 1 MODE.hyperparameter.c_value]);    % Linear Kernel, C=1; degree=1, c-SVM
725                                w = -SVs * AlphaY'*cl(1);  %Calculate decision hyperplane weight vector
726                                % ensure correct sign of weight vector and Bias according to class label
727                                Bias = -Bias * cl(1);
728
729                        elseif strcmp(MODE.TYPE, 'SVM:LOO');
730                                [a, Bias, g, inds]  = svcm_train(D, cl, MODE.hyperparameter.c_value); % C = 1;
731                                w = D(inds,:)' * (a(inds).*cl(inds)) ;
732
733                        elseif strcmp(MODE.TYPE, 'SVM:Gunn');
734                                [nsv, alpha, Bias,svi]  = svc(D, cl, 1, MODE.hyperparameter.c_value); % linear kernel, C = 1;
735                                w = D(svi,:)' * alpha(svi) * cl(1);
736                                Bias = mean(D*w);
737
738                        elseif strcmp(MODE.TYPE, 'SVM:KM');
739                                [xsup,w1,Bias,inds] = svmclass(D, cl, MODE.hyperparameter.c_value, 1, 'poly', 1); % C = 1;
740                                w = -D(inds,:)' * w1;
741
742                        else
743                                fprintf(2,'Error TRAIN_SVM: no SVM training algorithm available\n');
744                                return;
745                        end
746
747                        CC.weights(1,k) = -Bias;
748                        CC.weights(cix+1,k) = w;
749                end
750                CC.weights([1,cix+1],:) = s * CC.weights(cix+1,:) + sparse(1,1:M,CC.weights(1,:),sz2+1,M); % include pre-whitening transformation
751                CC.hyperparameter.c_value = MODE.hyperparameter.c_value;
752                CC.datatype = ['classifier:',lower(MODE.TYPE)];
753
754
755        elseif ~isempty(strfind(lower(MODE.TYPE),'csp'))
756                CC.datatype = ['classifier:',lower(MODE.TYPE)];
757                [classlabel,CC.Labels] = CL1M(classlabel);
758                CC.MD = repmat(NaN,[sz(2)+[1,1],length(CC.Labels)]);
759                CC.NN = CC.MD;
760                for k = 1:length(CC.Labels),
761                        %% [CC.MD(k,:,:),CC.NN(k,:,:)] = covm(D(classlabel==CC.Labels(k),:),'E');
762                        ix = classlabel==CC.Labels(k);
763                        if isempty(W)
764                                [CC.MD(:,:,k),CC.NN(:,:,k)] = covm(D(ix,:), 'E');
765                        else
766                                [CC.MD(:,:,k),CC.NN(:,:,k)] = covm(D(ix,:), 'E', W(ix));
767                        end
768                end
769                ECM = CC.MD./CC.NN;
770                W   = csp(ECM,'CSP3');
771                %%% ### This is a hack ###
772                CC.FiltA = 50;
773                CC.FiltB = ones(CC.FiltA,1);
774                d   = filtfilt(CC.FiltB,CC.FiltA,(D*W).^2);
775                CC.csp_w = W;
776                CC.CSP = train_sc(log(d),classlabel);
777
778
779        else          % Linear and Quadratic statistical classifiers
780                CC.datatype = ['classifier:statistical:',lower(MODE.TYPE)];
781                [classlabel,CC.Labels] = CL1M(classlabel);
782                CC.MD = repmat(NaN,[sz(2)+[1,1],length(CC.Labels)]);
783                CC.NN = CC.MD;
784                for k = 1:length(CC.Labels),
785                        ix = classlabel==CC.Labels(k);
786                        if isempty(W)
787                                [CC.MD(:,:,k),CC.NN(:,:,k)] = covm(D(ix,:), 'E');
788                        else
789                                [CC.MD(:,:,k),CC.NN(:,:,k)] = covm(D(ix,:), 'E', W(ix));
790                        end
791                end
792
793                ECM = CC.MD./CC.NN;
794                NC  = size(CC.MD);
795                if strncmpi(MODE.TYPE,'LD',2) || strncmpi(MODE.TYPE,'FDA',3) || strncmpi(MODE.TYPE,'FLDA',3),
796
797                        %if NC(1)==2, NC(1)=1; end                % linear two class problem needs only one discriminant
798                        CC.weights = repmat(NaN,NC(2),NC(3));     % memory allocation
799                        type = MODE.TYPE(3)-'0';
800
801                        ECM0 = squeeze(sum(ECM,3));  %decompose ECM
802                        for k = 1:NC(3);
803                                ix = [1:k-1,k+1:NC(3)];
804                                dM = CC.MD(:,1,k)./CC.NN(:,1,k) - sum(CC.MD(:,1,ix),3)./sum(CC.NN(:,1,ix),3);
805                                switch (type)
806                                        case 2          % LD2
807                                                ecm0 = (sum(ECM(:,:,ix),3)/(NC(3)-1) + ECM(:,:,k));
808                                        case 4          % LD4
809                                                ecm0 = 2*(sum(ECM(:,:,ix),3) + ECM(:,:,k))/NC(3);
810                                                % ecm0 = sum(CC.MD,3)./sum(CC.NN,3);
811                                        case 5          % LD5
812                                                ecm0 = ECM(:,:,k);
813                                        case 6          % LD6
814                                                ecm0 = sum(CC.MD(:,:,ix),3)./sum(CC.NN(:,:,ix),3);
815                                        otherwise       % LD3, LDA, FDA
816                                                ecm0 = ECM0;
817                                end
818                                if isfield(MODE.hyperparameter,'gamma')
819                                        ecm0 = ecm0 + mean(diag(ecm0))*eye(size(ecm0))*MODE.hyperparameter.gamma;
820                                end
821
822                                CC.weights(:,k) = ecm0\dM;
823
824                        end
825                        %CC.weights = sparse(CC.weights);
826
827                elseif strcmpi(MODE.TYPE,'RDA');
828                        if isfield(MODE,'hyperparameter')
829                                CC.hyperparameter = MODE.hyperparameter;
830                        end
831                        % default values
832                        if ~isfield(CC.hyperparameter,'gamma')
833                                CC.hyperparameter.gamma = 0;
834                        end
835                        if ~isfield(CC.hyperparameter,'lambda')
836                                CC.hyperparameter.lambda = 1;
837                        end
838                else
839                        ECM0 = sum(ECM,3);
840                        nn = ECM0(1,1,1);       % number of samples in training set for class k
841                        XC = squeeze(ECM0(:,:,1))/nn;           % normalize correlation matrix
842                        M  = XC(1,2:NC(2));             % mean
843                        S  = XC(2:NC(2),2:NC(2)) - M'*M;% covariance matrix
844
845                        try
846                                [v,d]=eig(S);
847                                U0 = v(diag(d)==0,:);
848                                CC.iS2 = U0*U0';
849                        end
850
851                        %M  = M/nn; S=S/(nn-1);
852                        ICOV0 = inv(S);
853                        CC.iS0 = ICOV0;
854                        % ICOV1 = zeros(size(S));
855                        for k = 1:NC(3),
856                                %[M,sd,S,xc,N] = decovm(ECM{k});  %decompose ECM
857                                %c  = size(ECM,2);
858                                nn = ECM(1,1,k);% number of samples in training set for class k
859                                XC = squeeze(ECM(:,:,k))/nn;% normalize correlation matrix
860                                M  = XC(1,2:NC(2));% mean
861                                S  = XC(2:NC(2),2:NC(2)) - M'*M;% covariance matrix
862                                %M  = M/nn; S=S/(nn-1);
863
864                                %ICOV(1) = ICOV(1) + (XC(2:NC(2),2:NC(2)) - )/nn
865
866                                CC.M{k}   = M;
867                                CC.IR{k}  = [-M;eye(NC(2)-1)]*inv(S)*[-M',eye(NC(2)-1)];  % inverse correlation matrix extended by mean
868                                CC.IR0{k} = [-M;eye(NC(2)-1)]*ICOV0*[-M',eye(NC(2)-1)];  % inverse correlation matrix extended by mean
869                                d = NC(2)-1;
870                                if exist('OCTAVE_VERSION','builtin')
871                                        S = full(S);
872                                end
873                                CC.logSF(k)  = log(nn) - d/2*log(2*pi) - det(S)/2;
874                                CC.logSF2(k) = -2*log(nn/sum(ECM(:,1,1)));
875                                CC.logSF3(k) = d*log(2*pi) + log(det(S));
876                                CC.logSF4(k) = log(det(S)) + 2*log(nn);
877                                CC.logSF5(k) = log(det(S));
878                                CC.logSF6(k) = log(det(S)) - 2*log(nn/sum(ECM(:,1,1)));
879                                CC.logSF7(k) = log(det(S)) + d*log(2*pi) - 2*log(nn/sum(ECM(:,1,1)));
880                                CC.logSF8(k) = sum(log(svd(S))) + log(nn) - log(sum(ECM(:,1,1)));
881                                CC.SF(k) = nn/sqrt((2*pi)^d * det(S));
882                                %CC.datatype='LLBC';
883                        end
884                end
885        end
886end
887
888function [CL101,Labels] = cl101(classlabel)
889        %% convert classlabels to {-1,1} encoding
890
891        if (all(classlabel>=0) && all(classlabel==fix(classlabel)) && (size(classlabel,2)==1))
892                M = max(classlabel);
893                if M==2,
894                        CL101 = (classlabel==2)-(classlabel==1);
895                else
896                        CL101 = zeros(size(classlabel,1),M);
897                        for k=1:M,
898                                %% One-versus-Rest scheme
899                                CL101(:,k) = 2*real(classlabel==k) - 1;
900                        end
901                end
902                CL101(isnan(classlabel),:) = NaN; %% or zero ???
903
904        elseif all((classlabel==1) | (classlabel==-1)  | (classlabel==0) )
905                CL101 = classlabel;
906                M = size(CL101,2);
907        else
908                classlabel,
909                error('format of classlabel unsupported');
910        end
911        Labels = 1:M;
912        return;
913end
914
915
916function [cl1m, Labels] = CL1M(classlabel)
917        %% convert classlabels to 1..M encoding
918        if (all(classlabel>=0) && all(classlabel==fix(classlabel)) && (size(classlabel,2)==1))
919                cl1m = classlabel;
920
921        elseif all((classlabel==1) | (classlabel==-1) | (classlabel==0) )
922                CL101 = classlabel;
923                M = size(classlabel,2);
924                if any(sum(classlabel==1,2)>1)
925                        warning('invalid format of classlabel - at most one category may have +1');
926                end
927                if (M==1),
928                        cl1m = (classlabel==-1) + 2*(classlabel==+1);
929                else
930                        [tmp, cl1m] = max(classlabel,[],2);
931                        if any(tmp ~= 1)
932                                warning('some class might not be properly represented - you might what to add another column to classlabel = [max(classlabel,[],2)<1,classlabel]');
933                        end
934                        cl1m(tmp<1)= 0; %% or NaN ???
935                end
936        else
937                classlabel
938                error('format of classlabel unsupported');
939        end
940        Labels = 1:max(cl1m);
941        return;
942end
943