Tue 27 Aug 00:14:56 CEST 2024

test/test-rl1.js

@@ -0,0 +1,134 @@
+// Maze of Torment World
+// Temporal Difference Learning (TD)
+
+var height=7,width=7,start=0;
+// 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], 
+]
+
+var states = []
+maze.forEach(function (row) {
+  states=states.concat(row)
+})
+
+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;
+}
+var actions = ['left','right','up','down']
+
+var env = {};
+
+env.steps = 0;
+env.iteration = 0;
+
+// required by learner
+env.getNumStates      = function() { return height*width; }
+env.getMaxNumActions  = function() { return actions.length; }
+env.nextState = function(state,action) {
+  var nx, ny, nextstate;
+  var x = env.stox(state);
+  var y = env.stoy(state);
+  switch (states[state]) {
+    case f: 
+    case s: 
+      // 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 = ny*width+nx;
+      way[ny][nx]=1;
+      env.steps++;
+      break;
+    case w:
+      // cliff! oh no! Should not happend - see below
+      // print('Back to start...')
+      nextstate=start;
+      reset(false)
+      env.iteration++;
+      break;
+    case d:
+      // agent wins! teleport to start
+      print('['+env.iteration+'] Found destination !!!!!!! steps='+env.steps)
+      reset(true);
+      nextstate=start;
+      env.iteration++;
+      break;
+  }
+//print(state,action,nextstate)
+  return nextstate;
+}
+env.reward = function (state,action,nextstate) {
+  // reward of being in s, taking action a, and ending up in ns
+  var reward;
+  // If the destination was found, weight the reward with the number of steps
+  // return best reward for shortest path
+  if (states[state]==d) reward = 1.0-(env.steps/100)
+  else if (states[state]==w) reward = -1;
+  else reward = 0;
+    return reward;
+}
+env.allowedActions    = function(state) { 
+  var x = env.stox(state), y = env.stoy(state);
+  var actions=[];
+  if (x>0) actions.push('left');
+  if (y>0) actions.push('up');
+  if (x<width-1) actions.push('right');
+  if (y<height-1) actions.push('down');
+  return actions 
+}
+
+// utils
+env.stox = function (s) { return s % width }
+env.stoy = function (s) { return Math.floor(s / width) }
+
+reset()
+
+// create the DQN agent
+var model = ml.learn({
+  algorithm   : ml.ML.RL,
+  kind        : ml.ML.TDAgent,
+  actions     : actions,
+  
+  // specs
+  alpha       : 0.1,  // value function learning rate
+  beta        : 0.2,  // learning rate for smooth policy update
+  epsilon     : 0.2,  // initial epsilon for epsilon-greedy policy, [0, 1)
+  gamma       : 0.5,  // discount factor, [0, 1)
+  lambda      : 0,    // eligibility trace decay, [0,1). 0 = no eligibility traces
+  planN       : 5,   // number of planning steps per iteration. 0 = no planning
+  replacing_traces : true,
+  smooth_policy_update : false,
+  update : 'qlearn',  // 'qlearn' or 'sarsa'
+  
+  environment : env
+}); 
+
+print(model)
+print(toJSON(model).length+' Bytes')
+
+
+var state = start;  // uppel left corner
+var timer = setInterval(function(){ // start the learning loop
+  var action = ml.action(model,state); // s is an integer
+  //... execute action in environment and get the reward
+  // print(state,action,states[state])
+  var ns = env.nextState(state,action);
+  var reward = env.reward(ns)-0.01
+  ml.update(model,reward)
+  state = ns
+}, 1);