function varargout = tspo_ga(varargin)
% Initialize default configuration
defaultConfig.xy = 10*rand(50,2);
defaultConfig.dmat = [];
defaultConfig.popSize = 100;
defaultConfig.numIter = 1e4;
defaultConfig.showProg = true;
defaultConfig.showResult = true;
defaultConfig.showWaitbar = false;
% Interpret user configuration inputs
if ~nargin
userConfig = struct();
elseif isstruct(varargin{1})
userConfig = varargin{1};
else
try
userConfig = struct(varargin{:});
catch
error('Expected inputs are either a structure or parameter/value pairs');
end
end
% Override default configuration with user inputs
configStruct = get_config(defaultConfig,userConfig);
% Extract configuration
xy = configStruct.xy;
dmat = configStruct.dmat;
popSize = configStruct.popSize;
numIter = configStruct.numIter;
showProg = configStruct.showProg;
showResult = configStruct.showResult;
showWaitbar = configStruct.showWaitbar;
if isempty(dmat)
nPoints = size(xy,1);
a = meshgrid(1:nPoints);
dmat = reshape(sqrt(sum((xy(a,:)-xy(a',:)).^2,2)),nPoints,nPoints);
end
% Verify Inputs
[N,dims] = size(xy);
[nr,nc] = size(dmat);
if N ~= nr || N ~= nc
error('Invalid XY or DMAT inputs!')
end
n = N;
% Sanity Checks
popSize = 4*ceil(popSize/4);
numIter = max(1,round(real(numIter(1))));
showProg = logical(showProg(1));
showResult = logical(showResult(1));
showWaitbar = logical(showWaitbar(1));
% Initialize the Population
pop = zeros(popSize,n);
pop(1,:) = (1:n);
for k = 2:popSize
pop(k,:) = randperm(n);
end
% Run the GA
globalMin = Inf;
totalDist = zeros(1,popSize);
distHistory = zeros(1,numIter);
tmpPop = zeros(4,n);
newPop = zeros(popSize,n);
if showProg
figure('Name','TSPO_GA | Current Best Solution','Numbertitle','off');
hAx = gca;
end
if showWaitbar
hWait = waitbar(0,'Searching for near-optimal solution ...');
end
for iter = 1:numIter
% Evaluate Each Population Member (Calculate Total Distance)
for p = 1:popSize
d = 0; % Open Path
for k = 2:n
d = d + dmat(pop(p,k-1),pop(p,k));
end
totalDist(p) = d;
end
% Find the Best Route in the Population
[minDist,index] = min(totalDist);
distHistory(iter) = minDist;
if minDist < globalMin
globalMin = minDist;
optRoute = pop(index,:);
if showProg
% Plot the Best Route
if dims > 2, plot3(hAx,xy(optRoute,1),xy(optRoute,2),xy(optRoute,3),'r.-');
else plot(hAx,xy(optRoute,1),xy(optRoute,2),'r.-'); end
title(hAx,sprintf('Total Distance = %1.4f, Iteration = %d',minDist,iter));
drawnow;
end
end
% Genetic Algorithm Operators
randomOrder = randperm(popSize);
for p = 4:4:popSize
rtes = pop(randomOrder(p-3:p),:);
dists = totalDist(randomOrder(p-3:p));
[ignore,idx] = min(dists); %#ok
bestOf4Route = rtes(idx,:);
routeInsertionPoints = sort(ceil(n*rand(1,2)));
I = routeInsertionPoints(1);
J = routeInsertionPoints(2);
for k = 1:4 % Mutate the Best to get Three New Routes
tmpPop(k,:) = bestOf4Route;
switch k
case 2 % Flip
tmpPop(k,I:J) = tmpPop(k,J:-1:I);
case 3 % Swap
tmpPop(k,[I J]) = tmpPop(k,[J I]);
case 4 % Slide
tmpPop(k,I:J) = tmpPop(k,[I+1:J I]);
otherwise % Do Nothing
end
end
newPop(p-3:p,:) = tmpPop;
end
pop = newPop;
% Update the waitbar
if showWaitbar && ~mod(iter,ceil(numIter/325))
waitbar(iter/numIter,hWait);
end
end
if showWaitbar
close(hWait);
end
if showResult
% Plots the GA Results
figure('Name','TSPO_GA | Results','Numbertitle','off');
subplot(2,2,1);
pclr = ~get(0,'DefaultAxesColor');
if dims > 2, plot3(xy(:,1),xy(:,2),xy(:,3),'.','Color',pclr);
else plot(xy(:,1),xy(:,2),'.','Color',pclr); end
title('City Locations');
subplot(2,2,2);
imagesc(dmat(optRoute,optRoute));
title('Distance Matrix');
subplot(2,2,3);
if dims > 2, plot3(xy(optRoute,1),xy(optRoute,2),xy(optRoute,3),'r.-');
else plot(xy(optRoute,1),xy(optRoute,2),'r.-'); end
title(sprintf('Total Distance = %1.4f',minDist));
subplot(2,2,4);
plot(distHistory,'b','LineWidth',2);
title('Best Solution History');
set(gca,'XLim',[0 numIter+1],'YLim',[0 1.1*max([1 distHistory])]);
end
% Return Output
if nargout
resultStruct = struct( ...
'xy', xy, ...
'dmat', dmat, ...
'popSize', popSize, ...
'numIter', numIter, ...
'showProg', showProg, ...
'showResult', showResult, ...
'showWaitbar', showWaitbar, ...
'optRoute', optRoute, ...
'minDist', minDist);
varargout = {resultStruct};
end
end
