public boolean[] getAction() {
// Take random action with some probability
if (numGenerator.nextFloat() < getEpsilonGreedy()) {
int randIndex = numGenerator.nextInt(possibleActions.size());
action = possibleActions.get(randIndex);
}
// Otherwise return best action (calculated in integrateObservation)
return action;
}
private double[][] extractFeatures(StateActionPair sap) {
// Feature extractor
int[] state = sap.getState();
double[][] features = new double[1][numFeatures];
int ind = 0;
for (int i = 0; i < state.length; i++) {
features[0][ind] = (state[i] == 0) ? 0.0 : 1.0;
ind++;
}
for (int i = 0; i < possibleActions.size(); i++) {
if (Arrays.equals(possibleActions.get(i), sap.getAction())) {
features[0][ind] = 1.0;
break;
}
ind++;
}
// Bias term
features[0][numFeatures - 1] = 1.0;
return (features);
}
private boolean[] findBestAction(Environment env, int[] state) {
ArrayList<boolean[]> allActions = getPossibleActions(env);
// Calculate score for all possible next actions
double[] qscores = new double[allActions.size()];
for (int i = 0; i < allActions.size(); i++) {
boolean[] action = allActions.get(i);
StateActionPair sap = new StateActionPair(state, action);
qscores[i] = evalScore(sap);
}
// Find ArgMax over all actions using calculated scores
int ind = numGenerator.nextInt(allActions.size());
boolean[] bestAction = allActions.get(ind);
bestScore = qscores[ind];
for (int i = 1; i < allActions.size(); i++) {
if (qscores[i] > bestScore) {
bestScore = qscores[i];
bestAction = allActions.get(i);
}
}
// System.out.println(bestScore);
return (bestAction);
}
public void integrateObservation(int[] succState, float currFitScore) {
// If this is the first observation of the round
if (state == null) {
state = succState;
action = new boolean[Environment.numberOfKeys];
prevFitScore = 0;
bestScore = 0;
possibleActions = getPossibleActions(environment);
// Unpack Values
if (learnedParams.containsKey("weights")) {
iter = (Iteration) learnedParams.get("iter");
rm = (ReplayMemory) learnedParams.get("rm");
weights = (HashMap<String, double[][]>) learnedParams.get("weights");
System.out.println("Starting Simulation at iteration : " + Integer.toString(iter.value));
} else {
// If this is the first observation of the simulation/trials
rm = new ReplayMemory(GlobalOptions.replaySize);
weights = new HashMap<String, double[][]>();
iter = new Iteration(1);
learnedParams.put("weights", weights);
learnedParams.put("rm", rm);
learnedParams.put("iter", iter);
}
if (net == null) {
numFeatures = state.length + possibleActions.size() + 1;
int numActions = possibleActions.size();
// Network Architecture
List<LayerSpec> layerSpecs = new ArrayList<LayerSpec>();
// Layer 1:
layerSpecs.add(
new LayerSpec(LayerFactory.TYPE_FULLY_CONNECTED, numFeatures, GlobalOptions.h1Size));
layerSpecs.add(
new LayerSpec(LayerFactory.TYPE_RELU, GlobalOptions.batchSize, GlobalOptions.h1Size));
// Layer 2:
layerSpecs.add(
new LayerSpec(
LayerFactory.TYPE_FULLY_CONNECTED, GlobalOptions.h1Size, GlobalOptions.h2Size));
layerSpecs.add(
new LayerSpec(LayerFactory.TYPE_RELU, GlobalOptions.batchSize, GlobalOptions.h2Size));
// Layer 3:
layerSpecs.add(new LayerSpec(LayerFactory.TYPE_FULLY_CONNECTED, GlobalOptions.h2Size, 1));
net = new NeuralNet(layerSpecs, weights);
}
}
// state and action denote (s,a) while succState and succAction denote (s'a')
// Reward denotes r
StateActionPair SAP = new StateActionPair(state, action);
boolean[] succAction = findBestAction(environment, succState);
StateActionPair succSAP = new StateActionPair(succState, succAction);
double succBestScore = evalScore(succSAP);
float reward = currFitScore - prevFitScore;
if (GlobalOptions.useIndicatorRewards) {
if (reward != 0) reward = reward > 0 ? 1.0f : -1.0f;
}
double trueScore = reward + GlobalOptions.dicount * succBestScore;
rm.addMemory(extractFeatures(SAP)[0], trueScore);
// Annealed learning rate and epsilon greedy
if (iter.value % GlobalOptions.DECAY_STEP == 0
&& !GlobalOptions.testTime
&& GlobalOptions.LR > GlobalOptions.MIN_LR) {
GlobalOptions.LR = GlobalOptions.LR * GlobalOptions.decayFactor;
// RANDOM_ACTION_EPSILON = RANDOM_ACTION_EPSILON * DECAY_FACTOR;
System.out.println(
"Decay Step - LR : "
+ Double.toString(GlobalOptions.LR)
+ " Epsilon : "
+ Double.toString(randomJump));
}
// only do this update on every n-th iteration
if (iter.value % GlobalOptions.UPDATE_INTERVAL == 0 && !GlobalOptions.testTime) {
List<double[][]> batch = rm.sample(GlobalOptions.batchSize);
double[][] trainX = batch.get(0);
double[][] trainy = batch.get(1);
double[][] pred = net.forward(trainX);
double[][] trainError = Matrix.subtract(pred, trainy);
double regError = 0.5 * GlobalOptions.regularizationLamda * net.getWeightSq();
trainError = Matrix.scalarAdd(trainError, regError);
net.backprop(trainError, GlobalOptions.LR, GlobalOptions.regularizationLamda);
}
if (iter.value % GlobalOptions.STAT_INTERVAL == 0 && !GlobalOptions.testTime) {
// Print learning statistics - on every nth iteration
double error = (evalScore(SAP) - trueScore);
stats.addError(error);
stats.addWeights(net);
stats.addLearningRate(GlobalOptions.LR);
stats.addEpsilonGreedy(randomJump);
stats.flush();
}
// Update Persistent Parameters
iter.value++;
state = succState;
action = succAction;
prevFitScore = currFitScore;
}