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Modify Policy Evaluation Solution.ipynb according to David Silver's slides. #166

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Modify Policy Evaluation Solution.ipynb according to David Silver's slides. #166

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43 changes: 28 additions & 15 deletions DP/Policy Evaluation Solution.ipynb
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,9 @@
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"from IPython.core.debugger import set_trace\n",
Expand All @@ -18,7 +20,9 @@
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"pp = pprint.PrettyPrinter(indent=2)\n",
Expand All @@ -28,7 +32,9 @@
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def policy_eval(policy, env, discount_factor=1.0, theta=0.00001):\n",
Expand Down Expand Up @@ -57,9 +63,11 @@
" # Look at the possible next actions\n",
" for a, action_prob in enumerate(policy[s]):\n",
" # For each action, look at the possible next states...\n",
" v_tmp = 0\n",
" for prob, next_state, reward, done in env.P[s][a]:\n",
" # Calculate the expected value. Ref: Sutton book eq. 4.6.\n",
" v += action_prob * prob * (reward + discount_factor * V[next_state])\n",
" # Calculate v_k+1(current_state). Ref: page 8 of David Silver's slides for lecture 3\n",
" v_tmp += prob * V[next_state]\n",
" v += action_prob * (reward + discount_factor * v_tmp)\n",
" # How much our value function changed (across any states)\n",
" delta = max(delta, np.abs(v - V[s]))\n",
" V[s] = v\n",
Expand All @@ -72,7 +80,9 @@
{
"cell_type": "code",
"execution_count": 4,
"metadata": {},
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"random_policy = np.ones([env.nS, env.nA]) / env.nA\n",
Expand All @@ -91,8 +101,7 @@
"Value Function:\n",
"[ 0. -13.99993529 -19.99990698 -21.99989761 -13.99993529\n",
" -17.9999206 -19.99991379 -19.99991477 -19.99990698 -19.99991379\n",
" -17.99992725 -13.99994569 -21.99989761 -19.99991477 -13.99994569\n",
" 0. ]\n",
" -17.99992725 -13.99994569 -21.99989761 -19.99991477 -13.99994569 0. ]\n",
"\n",
"Reshaped Grid Value Function:\n",
"[[ 0. -13.99993529 -19.99990698 -21.99989761]\n",
Expand All @@ -116,7 +125,9 @@
{
"cell_type": "code",
"execution_count": 6,
"metadata": {},
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"# Test: Make sure the evaluated policy is what we expected\n",
Expand All @@ -127,28 +138,30 @@
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"metadata": {
"collapsed": true
},
"outputs": [],
"source": []
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"display_name": "Python 2",
"language": "python",
"name": "python3"
"name": "python2"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
"version": 2
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.6.4"
"pygments_lexer": "ipython2",
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}
},
"nbformat": 4,
Expand Down