Tue 27 Aug 00:14:56 CEST 2024

test/test-rl4.js

@@ -0,0 +1,152 @@
+// Maze of Torment World
+// Deep-Q Learning (DQN)
+
+var height=7,width=7,start,dest;
+// 0: free place, 1: start, 2: destination, -1: wall
+var f=0,s=1,d=2,w=-1
+var maze = [
+[s,f,w,d,w,f,f], 
+[f,f,w,f,w,f,f], 
+[f,f,w,f,f,f,f], 
+[f,f,w,w,w,f,f], 
+[f,f,f,f,f,f,f], 
+[f,f,f,f,w,w,w], 
+[f,w,f,f,f,f,f], 
+]
+
+// world states
+var states = []
+maze.forEach(function (row,j) {
+  states=states.concat(row)
+  row.forEach(function (cell,i) {
+    if (cell==s) start=i+j*width;
+    if (cell==d) dest={x:i,y:j}
+  })
+})
+
+var way = []
+function reset (pr) {
+  if (pr) print(way.join('\n'))
+  way = maze.map(function (row) { 
+    return row.map(function (col) { return col==s?1:(col==w?'w':0) })})
+  env.steps=0;
+  env.good=0;
+  env.error=0;
+  env.iteration++;
+}
+var actions = ['left','right','up','down']
+
+// Agent sensor states (perception)
+// Distances {N,S,W,E} to boundaries and walls, distance
+var sensors = [0,0,0,0,0]
+
+var env = {};
+
+env.steps = 0;
+env.iteration = 0;
+env.error = 0;
+env.good = 0;
+env.last = 0;
+
+// required by learner
+env.getNumStates      = function() { return sensors.length /*!!*/ }
+env.getMaxNumActions  = function() { return actions.length; }
+
+// internals
+env.nextState = function(state,action) {
+  var nx, ny, nextstate;
+  var x = env.stox(state);
+  var y = env.stoy(state);
+  // free place to move around
+  switch (action) {
+    case 'left'  : nx=x-1; ny=y; break;
+    case 'right' : nx=x+1; ny=y; break;
+    case 'up'    : ny=y-1; nx=x; break;
+    case 'down'  : ny=y+1; nx=x; break;
+  }
+  nextstate = env.xytos(nx,ny);
+  if (nx<0 || ny<0 || nx >= width || ny >= height ||
+      states[nextstate]==w) {
+    nextstate=-1;
+    return nextstate;
+  }
+  way[ny][nx]=1;
+  env.steps++;
+  return nextstate;
+}
+env.reward = function (state,action,nextstate) {
+  // reward of being in s, taking action a, and ending up in ns
+  var reward;
+  var dist1=Math.sqrt(Math.pow(dest.x-env.stox(nextstate),2)+
+                      Math.pow(dest.y-env.stoy(nextstate),2))
+  var dist2=Math.sqrt(Math.pow(dest.x-env.stox(state),2)+
+                      Math.pow(dest.y-env.stoy(state),2))
+  if (nextstate==env.laststate) reward = -10; // avoid ping-pong
+  else if (nextstate==-1) reward = -100; // wall hit or outside world
+  else if (dist1 < 1) reward = 100-env.steps/10; // destination found
+  else reward = (dist1-dist2)<0?dist1/10:-dist1/10; // on the way
+  env.laststate=nextstate;
+  return reward;
+}
+
+// Update sensors
+env.perception = function (state) {
+  var i,
+      dist=Math.sqrt(Math.pow(dest.x-env.stox(state),2)+
+                     Math.pow(dest.y-env.stoy(state),2)),
+      x = env.stox(state),
+      y = env.stoy(state),
+      sensors = [0,0,0,0,dist]; // N S W E
+  // Distances to obstacles
+  for(i=y;i>0;i--) { if (states[env.xytos(x,i)]==w) break }
+  sensors[0]=y-i-1;
+  for(i=y;i<height;i++) { if (states[env.xytos(x,i)]==w) break }
+  sensors[1]=i-y-1;
+  for(i=x;i>0;i--) { if (states[env.xytos(i,y)]==w) break }
+  sensors[2]=x-i-1;
+  for(i=x;i<width;i++) { if (states[env.xytos(i,y)]==w) break }
+  sensors[3]=i-x-1;
+  return sensors
+}
+// utils
+env.stox = function (s)    { return s % width }
+env.stoy = function (s)    { return Math.floor(s / width) }
+env.xytos = function (x,y) { return x+y*width }
+
+reset()
+
+// create the DQN agent
+var model = load('/tmp/rl.json')
+
+print(model)
+print(toJSON(model).length+' Bytes')
+
+var state = start;  // world state. upper left corner
+
+// The agent searches the destination with random walk
+// If the the destination was found, it jumps back to the start
+later(1,function(task){ // start the learning loop
+  sensors = env.perception(state);
+  var action = ml.action(model,sensors); // s is a vector
+  //... execute action in environment and get the reward
+  var ns = env.nextState(state,action);
+  var reward = env.reward(state,action,ns)
+  if (states[ns]==d) {
+    // destination found
+    print('iteration='+env.iteration,', reward='+reward,' action: steps='+env.good,'error='+env.error+' tderror='+
+          model.tderror)
+    ns=start;
+    reset(true);
+  }
+  if (ns==-1) env.error++;
+  else env.good++;
+// print(state,ns,sensors,reward)    
+  ml.update(model,reward)
+  state = ns==-1?state:ns
+  // state = ns==-1?start:ns
+  if (reward > 98.4) {
+    save('/tmp/rl.json',model);
+    kill(task);
+  }
+  return true;
+});