samer@4: % mt_get_transmat_near - Get transition matrix near given point in information space.
samer@4: %
samer@4: % mt_get_transmat_near ::
samer@4: %    mt_system ~'Melody Triangle system structure',
samer@4: %    natural   ~'voice Id (1 or greater)',
samer@4: %    K:natural ~'size of transition matrix',
samer@4: %    real      ~'X-coordinate',
samer@4: %    real      ~'Y-coordinate'
samer@4: % -> [[K,K]]   ~'transition matrix',
samer@4: %    [[1,3]]   ~'information coordinates'.
samer@4: %
samer@4: % A transition matrix will be chosen at random from amongst the ones
samer@4: % within a certain radius of the target point.
samer@4: % The selected transition matrix will be shown using mt_show_transmat,
samer@4: 
samer@4: 
samer@6: function [T,P,I]=mt_get_transmat_near(Sys,Id,K,X,Y,MinRad)
samer@4: 	logK=log(K);
samer@4: 	normpos = Sys.map([X;Y])';
samer@4: 	target = normpos*logK;
samer@4: 	tmats = Sys.transmats{K};
samer@4: 	info = Sys.info{K};
samer@4: 	L = size(info,1);
samer@6: 	if nargin<6, MinRad=0.01; end
samer@4: 
samer@4: 	% distance from target
samer@4: 	d2 = sum((info(:,1:2) - repmat(target,L,1)).^2,2);
samer@6: 	Mask = d2<=max(min(d2)*2,MinRad);
samer@4: 
samer@4: 	M = find(Mask);
samer@4: %	J = M(argmax(info(M,3)));
samer@15: 	J = M(randnat(length(M)));
samer@4: 	T = tmats(:,:,J);
samer@4: 	I = info(J,:);
samer@4: 	%Mask=2*int16(Mask); Mask(J)=1;
samer@4: 	%set(Sys.hScat{K},'CDATA',Mask); % scatc(info,Mask,16); rotate3d on;
samer@4: 	%figure(50); title(sprintf('pos: %.2f, %.2f',normpos(1), normpos(2)));
samer@9: 	if Sys.shuffle
samer@9: 		perm=randperm(K);
samer@9: 		T=T(perm,perm);
samer@9: 	end
samer@4: 	mt_show_transmat(Id,T,I);
samer@4: 	if nargin>1, P=Sys.revmap(I(1:2)'/logK); end
samer@4: end