Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
Drexel University or The Math Forum.



Fuzzy ARTMAP graphical demo, in Matlab
Posted:
Apr 16, 1997 5:12 PM


%%%%%%%% Implementation of a Fuzzy ARTMAP graphical demo, in Matlab %%%%%%%% Copyright (c) Rajeev Raizada, 16/4/97
disp('Graphical demo of Fuzzy ARTMAP learning the CircleintheSquare task.'); disp('Written by: Rajeev Raizada, '); disp(' Dept. of Cognitive and Neural Systems, '); disp(' Boston University.'); disp('E.mail: rajeev@cns.bu.edu'); disp(' '); disp(' Copyright (c) Rajeev Raizada, April 16th, 1997'); disp(' '); disp('Original Reference: Carpenter, G. A., Grossberg, S., Markuzon, N., '); disp(' Reynolds, J. H. and Rosen, D. B. (1992) '); disp('"Fuzzy ARTMAP: A Neural Network Architecture for Incremental Supervised'); disp('Learning of Analog Multidimensional Maps"'); disp('IEEE Transactions on Neural Networks, Vol. 3, No. 5, pp. 698713.'); disp(' '); disp('Category boxes are shown, along with the true decision boundary.'); disp('A category which resonates in the ARTa module for a given input lights up.'); disp('It may get reset by F_ab layer mismatch  it is then shown dotted.'); disp('Categories which match at F_ab can undergo learning.'); disp('Fast learning is used here, so a category box expands to contain the input.'); disp(' '); disp('Key: Presented point: *'); disp(' Category which predicts being INSIDE the circle: Solid line'); disp(' Category which predicts being OUTSIDE the circle: Dashed line'); disp(' Category resonating within ARTa module: Thick line'); disp(' Category reset by matchtracking: Dotted line'); disp(' Point sized category: marked by a cross: x'); disp(' '); disp('After each step, the program pauses. PRESS ANY KEY TO CONTINUE');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% The input and output
num_pats = 100; sq = 1; % Size of square r = sq/sqrt(2*pi); % Radius of circle so it's half area of square xcent = 0.5; ycent = 0.5; % Centre of circle a = [ xcent*ones(1,num_pats); ycent*ones(1,num_pats)] + ... sq*(0.5rand(2,num_pats)); % The x,y coords bmat = ((a(1,:)xcent).^2 + (a(2,:)ycent).^2) > r^2; bmat = [ bmat; 1bmat ]; % Change to [1 0], [0 1] form
ac = [a; ones(size(a))a]; % The complementcoded form of input a
%%%%%%%%%%%%%%%%%%%%%% If we are testing, make a grid of test inputs test_mode = 0; % Zero means we're testing, 1 means we're training
if test_mode==1, grain = 100; grx = linspace(xcentsq/2,xcent+sq/2,grain)'; gry = linspace(ycentsq/2,ycent+sq/2,grain)'; testpats = zeros(grain^2,2); % Initialise for i=1:grain, testpats(1+grain*(i1):i*grain,1) = grx; testpats(1+grain*(i1):i*grain,2) = ones(grain,1)*gry(i); end; testpats = [ testpats' ; 1testpats' ]; test_out = zeros(size(testpats,2),1); % Initialise output vector end;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Parameters
alpha = 0.001; % "Choice" parameter > 0. Set small for the % conservative limit (Fuzzy AM paper, Sect.3) beta = 1; % Learning rate. Set to 1 for fast learning rho_a_bar = 0; % Baseline vigilance for ARTa, in range [0,1] M = size(a,1); % Number of input components. Derived from data % NB: Total input size = 2M (due to complement) N = 20; % Number of available coding nodes % We start with some resonably large number % then, if we need to, can add more uncommitted L = size(bmat,1); % Number of output nodes. Derived from data rho_ab = 0.95; % Map field vigilance, in [0,1] epsilon = 0.001; % Fab mismatch raises ARTa vigilance to this % much above what is needed to reset ARTa num_patterns = size(a,2); % Number of input patterns (not in Carpenter)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Set up weights
w_a = ones(2*M,N); % Initial weights in ARTa. All set to 1 % Rowi, colj entry = weight from input node i % to F2 coding node j w_ab = ones(L,N); % Rowk, colj entry = weight from ARTa F2 % node j to Map Field node k committed_nodes = []; % Keep a record of which nodes get committed
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Main loop %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for i=1:num_patterns % Go through patterns one by one % Note: could shuffle order using randperm
A = ac(:,i); % Present input is ith column of ac
%%%%%%%%%%%%%%%%%%%%%%%%%%%% Plot all the category boxes figure(1); clf; %%%% Box xpath: u1, 1vc1, 1vc1, u1, u1 %%%% Box ypath: u2, u2, 1vc2, 1vc2, u2 hold on; h = plot([w_a(1,:); 1w_a(3,:); 1w_a(3,:); w_a(1,:); w_a(1,:)], ... [w_a(2,:); w_a(2,:); 1w_a(4,:); 1w_a(4,:); w_a(2,:)],''); %%%%%%%%%%%%%%%%%%%%% Make the outsidecircle predicting boxes dashed outboxes = find(w_ab(1,:)>w_ab(2,:)); % w_ab will be near [1 0] if outboxes ~= [], set( h(outboxes),'LineStyle',''); end; %%%%%%%%%%%%%%%% Mark all the pointsize boxes with crosses point_boxes = find(abs(sum(w_a)M)<0.001); for j=1:length(point_boxes), hpoint = plot(w_a(1,point_boxes(j)),w_a(2,point_boxes(j)),'x'); h(point_boxes(j)) = hpoint; %%% Make handle point to 'x' end; %%%%%%%%%%%%%%%%%%%%%%%%%%%% Plot the input vector title(['Presenting input number ' num2str(i) '. It is ( ' num2str(A(1)) ', ' num2str(A(2)) ' )' ]); plot(A(1),A(2),'*'); % Show the input with a star %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Draw the circle ang = 0:0.1:2.1*pi; plot(xcent+r*cos(ang),ycent+r*sin(ang),''); axis([0.1 1.1 0.1 1.1]); axis('equal'); drawnow; hold off; pause;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%% Find an ARTa resonance which gives Fab resonance too
%%%%%%%%%%%%%%%%% Initialise rho_a = rho_a_bar; % We start off with ARTa vigilance at baseline resonant_a = 0; % We're not resonating in the ARTa module yet resonant_ab = 0; % Not resonating in the Fab match layer either already_reset_nodes = []; % We haven't rest any ARTa nodes % for this input pattern yet
while resonant_ab == 0, %%%% We don't have an Fab match yet. %%%% So, we find an ARTa node and see what it predicts
while resonant_a == 0, %%% In search of a resonating ARTa node...
%%%%%%%%%%%%%%%%%%%%%%%%%% Find the winning, matching ARTa node N = size(w_a,2); % Count how many F2a nodes we have
A_for_each_F2_node = A * ones(1,N); % Matrix containing a copy of A for % each F2 node. Useful for Matlab
A_AND_w = min(A_for_each_F2_node,w_a); % Fuzzy AND = min
S = sum(A_AND_w); % Row vector of signals to F2 nodes
T = S ./ (alpha + sum(w_a)); % Choice function vector for F2
%%%%%%%%%%%%%%%%%%%%%%% Set all the reset nodes to zero
T(already_reset_nodes) = zeros(1,length(already_reset_nodes));
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Finding the winning node, J
[ Tmax, J ] = max(T); % Matlab function max works such that % J is the lowest index of max T elements, as % desired. J is the winning F2 category node y = zeros(1,N); y(J)=1; % Activities of F2. All zero, except J
w_J = w_a(:,J); % Weight vector into winning F2 node, J
x = min(A,w_J); % Fuzzy version of 2/3 rule. x is F1 activity % NB: We could also use Jth element of S % since the top line of the match fraction % I and w/I is sum(x), which is % S = sum(A_AND_w) from above
%%%%%%%%%%%%%%%% Testing if the winning node resonates in ARTa
if sum(x)/sum(A) >= rho_a, % If a match, we're done resonant_a = 1; % ARTa resonates end; % The while resonant_a == 0 command will stop looping % now, so we exit the while loop and go onto to Fab
if sum(x)/sum(A) < rho_a, % If mismatch then we reset resonant_a = 0; % So, still not resonating already_reset_nodes = [ already_reset_nodes J ]; end; % Record that node J has been % reset already. %%%%%%%%%% Creating a new node if we've reset all of them
if length(already_reset_nodes) == N, % If all F2a nodes reset w_a = [ w_a ones(2*M,1) ]; % Add uncommitted node to ARTa weight vector w_ab = [w_ab ones(L,1) ]; % Give the new F2a node a w_ab entry %%%%%%%%%%%%% Draw on the new uncommitted category box hold on; hnew = plot([0 1 1 0 0],[0 0 1 1 0],''); hold off; h = [ h; hnew ]; %%% Add handle for new box to list end; % Now go back and this new node should win
end; % End of the while loop searching for ARTa resonance % If resonant_a = 0, we pick the next highest Tj % and see if *that* node resonates, i.e. goto "while" % If resonant_a = 1, we have found an ARTa resonance, % namely node J % So we go on to see if we get Fab match with node J
%%%%%%%%%%%%%%%%%%%%%%%%%%%% Show the winning, matching ARTa node J set(h(J),'LineWidth',[4]); title(['Node ' num2str(J) ' was chosen by ARTa search. Choice = ' num2str(Tmax) '. Match = ' num2str(sum(x)/sum(A)) '. Rho_a = ' num2str(rho_a) ]); pause;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Match tracking
if test_mode==0, % If we're not testing b = bmat(:,i); % Desired output for input number i z = min(b,w_ab(:,J)); % Fab activation vector, z % (Called x_ab in Fuzzy ARTMAP paper)
%%%%%% Test for Fab resonance
if sum(z)/sum(b) >= rho_ab, % We have an Fab match resonant_ab = 1; title(['Desired: ' num2str(b) '. F_ab act: ' num2str(z) '. F_ab match score: ' num2str(sum(z)/sum(b)) '. Rho_ab = ' num2str(rho_ab) '. Match field resonates.']); pause; end; % This will cause us to leave the % while resonant_ab==0 loop and % go on to do learning.
if sum(z)/sum(b) < rho_ab, % We have an Fab mismatch resonant_ab = 0; % This makes us go through % the resonant_ab==0 loop again resonant_a = 0; % This makes us go through % ARTa search again, this % search being inside the % resonant_ab==0 loop %%%%% Increase rho_a vigilance. %%%%% This will cause F2a node J to get reset when %%%%% we go back through the ARTa search loop again. %%%%% Also, *for this input*, the abovebaseline %%%%% vigilance will cause a finer ARTa category to win
rho_a = sum(x)/sum(A) + epsilon;
%%%%%%%%%%%%%%%%%% Make the reset box dotted and thin title(['Desired out: ' num2str(b) '. F_ab act: ' num2str(z) '. Match field resets. Rho_a increased to ' num2str(rho_a) ]); set(h(J),'LineStyle',':'); set(h(J),'LineWidth',[0.5]); pause;
end; % End of Fab mismatch if
end; % End of "if test_mode==0"
if test_mode==1, % If we're testing there can be no Fab mismatch % We just want the prediction. resonant_ab = 1; % This is just to exit the loop test_out(i) = w_ab(:,J)/sum(w_ab(:,J)); % The prediction is the normalised w_ab vector end;
end; %%%%%%%%% End of the while resonant_ab==0 loop. %%%%%%%%% Now we have a resonating ARTa output which gives a match %%%%%%%%% at the Fab layer. %%%%%%%%% So, we go on to have learning in the w_a and w_ab weights
%%%%%%%%%%%%%%%%%%%%%%%%%%% Let the winning, matching node J learn
w_a(:,J) = beta*x + (1beta)*w_a(:,J); % NB: x = min(A,w_J) = I and w %%%% Learning on F1a <> f2a weights
w_ab(:,J) = beta*z + (1beta)*w_ab(:,J); % NB: z=min(b,w_ab(J))=b and w end; %%%%%%%%% End of considering this input. Now we go on to the next



