%FFNC Feed-forward neural net classifier back-end % % 	[W,HIST] = FFNC (ALG,A,UNITS,ITER,W_INI,T,FID)%% INPUT% 	ALG   Training algorithm: 'bpxnc' for back-propagation (default), 'lmnc' %         for Levenberg-Marquardt% 	A     Training dataset% 	UNITS Array indicating number of units in each hidden layer (default: [5])% 	ITER  Number of iterations to train (default: inf)% 	W_INI Weight initialisation network mapping (default: [], meaning %         initialisation by Matlab's neural network toolbox)% 	T     Tuning set (default: [], meaning use A)%   FID   File ID to write progress to (default [], see PRPROGRESS)%% OUTPUT% 	W     Trained feed-forward neural network mapping% 	HIST  Progress report (see below)%% DESCRIPTION % This function should not be called directly, but through one of its % front-ends, BPXNC or LMNC. Uses the Mathworks' Neural Network toolbox.% % SEE ALSO% MAPPINGS, DATASETS, BPXNC, LMNC, NEURC, RNNC, RBNC, PRPROGRESS% Copyright: R.P.W. Duin, duin@ph.tn.tudelft.nl% Faculty of Applied Physics, Delft University of Technology% P.O. Box 5046, 2600 GA Delft, The Netherlands% $Id: ffnc.m,v 1.17 2005/01/20 09:09:07 duin Exp $function [w,hist] = ffnc(alg,a,units,max_iter,w_ini,t,fid)	prtrace(mfilename);	% Settings for the different training algorithms.		if exist('nnet') ~= 7		error('Neural network toolbox not found')	end	if (strcmp(alg,'bpxnc'))		mapname = 'BP Neural Classf';		elseif (strcmp(alg,'lmnc'))		mapname = 'LM Neural Classf';	else		error('illegal training algorithm specified');	end;	% Check arguments	if (nargin < 7), fid = []; end;	if (nargin < 6) | (isempty(t))		prwarning(2,'no tuning set supplied, using training set for tuning (risk of overfit)');		if (nargin < 2), t = []; else, t = a; end;	end	if (nargin < 5) | (isempty(w_ini))		prwarning(3,'no initialisation supplied, using Nguyen-Widrow random initialisation');		w_ini = []; 	end	if (nargin < 4) | (isempty(max_iter))		prwarning(3,'no maximum number of iterations supplied, assuming infinite');		max_iter = inf; 	end	if (nargin < 3) | (isempty(units))		prwarning(2,'no network architecture specified, assuming one hidden layer of 5 units');		units = 5; 	end	if (nargin < 2) | (isempty(a))		w = mapping(alg,{units,max_iter,w_ini,t,fid});		w = setname(w,mapname);		hist = [];		return	end	% Training target values.	prwarning (4, 'using training targets 0.9/0.1');	target_high	= 0.9;	target_low	= 0.1;	% Check whether the dataset is valid.	islabtype(a,'crisp');	isvaldset(a,1,2); 							% At least 1 object per class, 2 classes	iscomdset(a,t);   							% Check whether training and tuning set match		[m,k,c] = getsize(a); lablist = getlablist(a); 	% Standard training parameters.	disp_freq   = inf; 	err_goal 		= 0.02/m;						% Mean-squared error goal, stop if reached	trnsf_fn	  = 'logsig';					% Transfer function  perf_fn     = 'mse';            % Performance function	% Settings for the different training algorithms.	tp.show   = disp_freq;	tp.time   = inf;	tp.goal   = err_goal;	if (strcmp(alg,'bpxnc'))		trnalg 					= 'traingdx'; 		lrnalg 					= 'learngdm';		burnin       		= 500;			% Never stop training before this many iters		tp.epochs    		= min(50,max_iter); 	% Iteration unit		tp.lr        		= 0.01;			% BP, initial value for adaptive learning rate		tp.lr_inc    		= 1.05;			% BP, multiplier for increasing learning rate		tp.lr_dec    		= 0.7;			% BP, multiplier for decreasing learning rate		tp.mc        		= 0.95;			% BP, momentum		tp.max_perf_inc = 1.04;			% BP, error ratio		tp.min_grad  		= 1e-6;			% BP, minimum performance gradient		tp.max_fail  		= 5;				% BP, maximum validation failures	elseif (strcmp(alg,'lmnc'))		trnalg 					= 'trainlm';  		lrnalg 					= 'learngdm';		burnin       		= 50;				% Never stop training before this many iters		tp.epochs 	 		= min(1,max_iter); 		% Iteration unit		tp.mem_reduc 		= 1;				% Trade-off between memory & speed		tp.max_fail  		= 1; 				% LM, maximum validation failures		tp.min_grad  		= 1e-6;			% LM, minimum gradient, stop if reached		tp.mu  	    		= 0.001;		% LM, initial value for adaptive learning rate		tp.mu_inc    		= 10;				% LM, multiplier for increasing learning rate		tp.mu_dec    		= 0.1;			% LM, multiplier for decreasing learning rate		tp.mu_max    		= 1e10;			% LM, maximum learning rate	end;		% Scale each feature to the range [0,1].	prwarning(3,'scaling such that training set features have range [0,1]');	ws = scalem(a,'domain'); a_scaled = a*ws; t_scaled = t*ws;	% Set number of network outputs: 1 for 2 classes, c for c > 2 classes.	if (c == 2), cout = 1; else, cout = c; end	% Create target matrix: row C contains a high value at position C,	% the correct class, and a low one for the incorrect ones (place coding).	if (cout > 1)    target = target_low * ones(c,c) + (target_high - target_low) * eye(c);	else		target = [target_high; target_low];	end	% Create the target arrays for both datasets.	target_a = target(getnlab(a),:)';	target_t = target(getnlab(t),:)';	% Create the network layout: K inputs, N(:) hidden units, COUT outputs.	numlayers = length(units)+1; numunits = [k,units(:)',cout];	transfer_fn = cellstr(char(ones(numlayers,1)*trnsf_fn));	% Create network and set training parameters. The network is initialised	% by the Nguyen-Widrow rule by default.	net = newff(ones(numunits(1),1)*[0 1],numunits(2:end),...							transfer_fn,trnalg,lrnalg,perf_fn);	net.trainParam = tp;	% If an initial network is specified, use its weights and biases.	if (~isempty(w_ini))		% Use given initialisation.		[data,lab,type_w] = get(w_ini,'data','labels','mapping_file');		if (strcmp(type_w,'sequential'))			a_scaled = a*data{1}; t_scaled = t*data{1}; ws = data{1};			[data,lab,type_w] = get(data{2},'data','labels','mapping_file');		end		% Check whether the mapping's dimensions are the same as the network's.		[kw,cw] = size(w_ini); net_ini = data{1};		if (~strcmp(type_w,'neurc')) | (kw ~= k) | (cw ~= c) | ...				(net.numInputs  ~= net_ini.numInputs) | ...				(net.numLayers  ~= net_ini.numLayers) | ...				(net.numOutputs ~= net_ini.numOutputs) | ...				any(net.biasConnect ~= net_ini.biasConnect) | ...				any(net.inputConnect ~= net_ini.inputConnect) | ...				any(net.outputConnect ~= net_ini.outputConnect)			error('incorrect size initialisation network supplied')		end		% Check whether the initialisation network was trained on the same data.		[dummy1,nlab,dummy2] = renumlab(lablist,lab);		if (max(nlab) > c)			error('initialisation network should be trained on same classes')		end		net.IW = net_ini.IW; net.LW = net_ini.LW; net.b = net_ini.b;	end	% Initialize loop 	opt_err = inf; opt_iter = inf; opt_net = net; 	iter = 0; this_iter = 1; hist = []; 		% Loop while:	% - training has not gone on for longer than 50 iterations or 2 times the 	%   number of iterations for which the error was minimal, and	% - the number of iterations does not exceed the maximum	% - the actual training function still performed some iterations  	prprogress(fid,'ffnn:  Feed-Forward Neural Net\n');				  while ((iter <= 2*opt_iter) | (iter < burnin)) & ...				(iter < max_iter) & (this_iter > 0) & (opt_err > 0)		% Call TRAIN, from Matlab's NN toolbox.		prwarning(4,'[%d] calling NNETs train', iter);		[net,tr] = train(net,+a_scaled',target_a);		this_iter = length(tr.epoch)-1; iter = iter + this_iter;		% Copy current learning rate as the one to start with for the next time.		if (strcmp(alg,'bpxnc'))			net.trainParam.lr = tr.lr(end);		else			net.trainParam.mu = tr.mu(end);		end;		% Map train and tuning set.  	w = mapping('neurc','trained',{net},lablist,k,c);  	w = setname(w,mapname); 			% Calculate mean squared errors (MSE).  	out_a = a_scaled*w; out_t = t_scaled*w; 		mse_a = mean(mean(((out_a(:,1:cout))-target_a').^2,1));		mse_t = mean(mean(((out_t(:,1:cout))-target_t').^2,1));		% Calculate classification errors.		e_a = testc(a_scaled,w); e_t = testc(t_scaled,w);			% If this error is minimal, store the iteration number and weights.  	if (e_t < opt_err)			prprogress(fid,'                --  minimum error %3.3f found, storing network  --\n', e_t);  		opt_err = e_t; opt_iter = iter; opt_net = net;   	end		w1 = cell2mat(net.IW); w1 = w1(:);		%w2 = cell2mat(net.LW'); bugfix, doesnot work for multilayer networks		%w2 = w2(:);		netLW = net.LW(:);		w2 = [];		for j=1: length(netLW)			ww = netLW{j};			w2 = [w2; ww(:)];		end  	hist = [hist; iter e_a e_t mse_a mse_t ...						mean([w1; w2].^2)];  	prprogress(fid,'  epochs:%5i  ea: %3.3f  et: %3.3f  msea: %3.3f  mset: %3.3f mean-w^2: %3.3f min_error: %3.3f\n', ...						hist(end,:), opt_err);  end  prprogress(fid,'ffnn finished\n');					% Create mapping.  w = ws*mapping('neurc','trained',{opt_net},lablist,k,c);  w = setname(w,mapname);	w = setcost(w,a);return