Newer
Older
" <span class=\"k\">return</span> <span class=\"n\">PlanningProblem</span><span class=\"p\">(</span><span class=\"n\">init</span><span class=\"o\">=</span><span class=\"s1\">'At(Home) & Sells(SM, Milk) & Sells(SM, Banana) & Sells(HW, Drill)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">goals</span><span class=\"o\">=</span><span class=\"s1\">'Have(Milk) & Have(Banana) & Have(Drill)'</span><span class=\"p\">,</span> \n",
" <span class=\"n\">actions</span><span class=\"o\">=</span><span class=\"p\">[</span><span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'Buy(x, store)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">'At(store) & Sells(store, x)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'Have(x)'</span><span class=\"p\">),</span>\n",
" <span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'Go(x, y)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">'At(x)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'At(y) & ~At(x)'</span><span class=\"p\">)])</span>\n",
"</pre></div>\n",
"</body>\n",
"</html>\n"
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"<IPython.core.display.HTML object>"
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{
"cell_type": "markdown",
"metadata": {},
"source": [
"**At(x):** Indicates that we are currently at **'x'** where **'x'** can be Home, SM (supermarket) or HW (Hardware store).\n",
"**~At(x):** Indicates that we are currently _not_ at **'x'**.\n",
"**Sells(s, x):** Indicates that item **'x'** can be bought from store **'s'**.\n",
"\n",
"**Have(x):** Indicates that we possess the item **'x'**."
]
},
{
"cell_type": "code",
"execution_count": 35,
"metadata": {
"collapsed": true
},
"shoppingProblem = shopping_problem()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Let's first check whether the goal state Have(Milk), Have(Banana), Have(Drill) is reached or not."
]
},
{
"cell_type": "code",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"False\n"
]
}
],
"source": [
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Let's look at the possible actions\n",
"**Buy(x, store):** Buy an item **'x'** from a **'store'** given that the **'store'** sells **'x'**.\n",
"**Go(x, y):** Go to destination **'y'** starting from source **'x'**."
"We now define a valid solution that will help us reach the goal.\n",
"The sequence of actions will then be carried out onto the `shoppingProblem` PlanningProblem."
]
},
{
"cell_type": "code",
"execution_count": 37,
"metadata": {
"collapsed": true
},
"solution = [expr('Go(Home, SM)'),\n",
" expr('Buy(Milk, SM)'),\n",
" expr('Buy(Banana, SM)'),\n",
" expr('Go(SM, HW)'),\n",
" expr('Buy(Drill, HW)')]\n",
"\n",
"for action in solution:\n",
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"We have taken the steps required to acquire all the stuff we need. \n",
"Let's see if we have reached our goal."
]
},
{
"cell_type": "code",
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"True"
]
},
"execution_count": 38,
"metadata": {},
"output_type": "execute_result"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"It has now successfully achieved the goal."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"This is a simple problem of putting on a pair of socks and shoes.\n",
"The problem is defined in the module as given below."
"cell_type": "code",
"execution_count": 39,
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"\n",
"<div class=\"highlight\"><pre><span></span><span class=\"k\">def</span> <span class=\"nf\">socks_and_shoes</span><span class=\"p\">():</span>\n",
" <span class=\"sd\">"""</span>\n",
"<span class=\"sd\"> SOCKS-AND-SHOES-PROBLEM</span>\n",
"\n",
"<span class=\"sd\"> A task of wearing socks and shoes on both feet</span>\n",
"\n",
"<span class=\"sd\"> Example:</span>\n",
"<span class=\"sd\"> >>> from planning import *</span>\n",
"<span class=\"sd\"> >>> ss = socks_and_shoes()</span>\n",
"<span class=\"sd\"> >>> ss.goal_test()</span>\n",
"<span class=\"sd\"> False</span>\n",
"<span class=\"sd\"> >>> ss.act(expr('RightSock'))</span>\n",
"<span class=\"sd\"> >>> ss.act(expr('RightShoe'))</span>\n",
"<span class=\"sd\"> >>> ss.act(expr('LeftSock'))</span>\n",
"<span class=\"sd\"> >>> ss.goal_test()</span>\n",
"<span class=\"sd\"> False</span>\n",
"<span class=\"sd\"> >>> ss.act(expr('LeftShoe'))</span>\n",
"<span class=\"sd\"> >>> ss.goal_test()</span>\n",
"<span class=\"sd\"> True</span>\n",
"<span class=\"sd\"> >>></span>\n",
"<span class=\"sd\"> """</span>\n",
"\n",
" <span class=\"k\">return</span> <span class=\"n\">PlanningProblem</span><span class=\"p\">(</span><span class=\"n\">init</span><span class=\"o\">=</span><span class=\"s1\">''</span><span class=\"p\">,</span>\n",
" <span class=\"n\">goals</span><span class=\"o\">=</span><span class=\"s1\">'RightShoeOn & LeftShoeOn'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">actions</span><span class=\"o\">=</span><span class=\"p\">[</span><span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'RightShoe'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">'RightSockOn'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'RightShoeOn'</span><span class=\"p\">),</span>\n",
" <span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'RightSock'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">''</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'RightSockOn'</span><span class=\"p\">),</span>\n",
" <span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'LeftShoe'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">'LeftSockOn'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'LeftShoeOn'</span><span class=\"p\">),</span>\n",
" <span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'LeftSock'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">''</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'LeftSockOn'</span><span class=\"p\">)])</span>\n",
"</pre></div>\n",
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"psource(socks_and_shoes)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"**LeftSockOn:** Indicates that we have already put on the left sock.\n",
"\n",
"**RightSockOn:** Indicates that we have already put on the right sock.\n",
"\n",
"**LeftShoeOn:** Indicates that we have already put on the left shoe.\n",
"\n",
"**RightShoeOn:** Indicates that we have already put on the right shoe.\n"
]
},
{
"cell_type": "code",
"execution_count": 40,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"socksShoes = socks_and_shoes()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Let's first check whether the goal state is reached or not."
]
},
{
"cell_type": "code",
"execution_count": 41,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"False"
]
},
"execution_count": 41,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"socksShoes.goal_test()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"As the goal state isn't reached, we will define a sequence of actions that might help us achieve the goal.\n",
"These actions will then be acted upon the `socksShoes` PlanningProblem to check if the goal state is reached."
]
},
{
"cell_type": "code",
"execution_count": 42,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"solution = [expr('RightSock'),\n",
" expr('RightShoe'),\n",
" expr('LeftSock'),\n",
" expr('LeftShoe')]"
]
},
{
"cell_type": "code",
"execution_count": 43,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"True"
]
},
"execution_count": 43,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"for action in solution:\n",
" socksShoes.act(action)\n",
" \n",
"socksShoes.goal_test()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"We have reached our goal."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Cake Problem"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"This problem requires us to reach the state of having a cake and having eaten a cake simlutaneously, given a single cake.\n",
"Let's first take a look at the definition of the `have_cake_and_eat_cake_too` problem in the module."
]
},
{
"cell_type": "code",
"execution_count": 44,
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"\n",
"<div class=\"highlight\"><pre><span></span><span class=\"k\">def</span> <span class=\"nf\">have_cake_and_eat_cake_too</span><span class=\"p\">():</span>\n",
" <span class=\"sd\">"""</span>\n",
"<span class=\"sd\"> [Figure 10.7] CAKE-PROBLEM</span>\n",
"\n",
"<span class=\"sd\"> A problem where we begin with a cake and want to </span>\n",
"<span class=\"sd\"> reach the state of having a cake and having eaten a cake.</span>\n",
"<span class=\"sd\"> The possible actions include baking a cake and eating a cake.</span>\n",
"\n",
"<span class=\"sd\"> Example:</span>\n",
"<span class=\"sd\"> >>> from planning import *</span>\n",
"<span class=\"sd\"> >>> cp = have_cake_and_eat_cake_too()</span>\n",
"<span class=\"sd\"> >>> cp.goal_test()</span>\n",
"<span class=\"sd\"> False</span>\n",
"<span class=\"sd\"> >>> cp.act(expr('Eat(Cake)'))</span>\n",
"<span class=\"sd\"> >>> cp.goal_test()</span>\n",
"<span class=\"sd\"> False</span>\n",
"<span class=\"sd\"> >>> cp.act(expr('Bake(Cake)'))</span>\n",
"<span class=\"sd\"> >>> cp.goal_test()</span>\n",
"<span class=\"sd\"> True</span>\n",
"<span class=\"sd\"> >>></span>\n",
"<span class=\"sd\"> """</span>\n",
"\n",
" <span class=\"k\">return</span> <span class=\"n\">PlanningProblem</span><span class=\"p\">(</span><span class=\"n\">init</span><span class=\"o\">=</span><span class=\"s1\">'Have(Cake)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">goals</span><span class=\"o\">=</span><span class=\"s1\">'Have(Cake) & Eaten(Cake)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">actions</span><span class=\"o\">=</span><span class=\"p\">[</span><span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'Eat(Cake)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">'Have(Cake)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'Eaten(Cake) & ~Have(Cake)'</span><span class=\"p\">),</span>\n",
" <span class=\"n\">Action</span><span class=\"p\">(</span><span class=\"s1\">'Bake(Cake)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">precond</span><span class=\"o\">=</span><span class=\"s1\">'~Have(Cake)'</span><span class=\"p\">,</span>\n",
" <span class=\"n\">effect</span><span class=\"o\">=</span><span class=\"s1\">'Have(Cake)'</span><span class=\"p\">)])</span>\n",
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"Since this problem doesn't involve variables, states can be considered similar to symbols in propositional logic.\n",
"\n",
"**Have(Cake):** Declares that we have a **'Cake'**.\n",
"\n",
"**~Have(Cake):** Declares that we _don't_ have a **'Cake'**."
]
},
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"cell_type": "code",
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"cakeProblem = have_cake_and_eat_cake_too()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"First let us check whether the goal state 'Have(Cake)' and 'Eaten(Cake)' are reached or not."
]
},
{
"cell_type": "code",
"execution_count": 46,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"False\n"
]
}
],
"source": [
"print(cakeProblem.goal_test())"
]
},
{
"cell_type": "markdown",
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"Let us look at the possible actions.\n",
"\n",
"**Bake(x):** To bake **' x '**.\n",
"\n",
"**Eat(x):** To eat **' x '**."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"We now define a valid solution that can help us reach the goal.\n",
"The sequence of actions will then be acted upon the `cakeProblem` PlanningProblem."
]
},
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"solution = [expr(\"Eat(Cake)\"),\n",
" expr(\"Bake(Cake)\")]\n",
"\n",
"for action in solution:\n",
" cakeProblem.act(action)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Now we have made actions to bake the cake and eat the cake. Let us check if we have reached the goal."
]
},
{
"cell_type": "code",
"execution_count": 48,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"True\n"
]
}
],
"source": [
"print(cakeProblem.goal_test())"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"It has now successfully achieved its goal i.e, to have and eat the cake."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"One might wonder if the order of the actions matters for this problem.\n",
"Let's see for ourselves."
]
},
{
"cell_type": "code",
"execution_count": 49,
"metadata": {},
"outputs": [
{
"ename": "Exception",
"evalue": "Action 'Bake(Cake)' pre-conditions not satisfied",
"output_type": "error",
"traceback": [
"\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
"\u001b[1;31mException\u001b[0m Traceback (most recent call last)",
"\u001b[1;32m<ipython-input-49-b340f831489f>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m 5\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 6\u001b[0m \u001b[1;32mfor\u001b[0m \u001b[0maction\u001b[0m \u001b[1;32min\u001b[0m \u001b[0msolution\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 7\u001b[1;33m \u001b[0mcakeProblem\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mact\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0maction\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[1;32m~\\Documents\\Python\\Data Science\\Machine Learning\\Aima\\planning.py\u001b[0m in \u001b[0;36mact\u001b[1;34m(self, action)\u001b[0m\n\u001b[0;32m 58\u001b[0m \u001b[1;32mraise\u001b[0m \u001b[0mException\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"Action '{}' not found\"\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mformat\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0maction_name\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 59\u001b[0m \u001b[1;32mif\u001b[0m \u001b[1;32mnot\u001b[0m \u001b[0mlist_action\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mcheck_precond\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0minit\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0margs\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 60\u001b[1;33m \u001b[1;32mraise\u001b[0m \u001b[0mException\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"Action '{}' pre-conditions not satisfied\"\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mformat\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0maction\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m 61\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0minit\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mlist_action\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0minit\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0margs\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mclauses\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 62\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n",
"\u001b[1;31mException\u001b[0m: Action 'Bake(Cake)' pre-conditions not satisfied"
]
}
],
"source": [
"cakeProblem = have_cake_and_eat_cake_too()\n",
"\n",
"solution = [expr('Bake(Cake)'),\n",
" expr('Eat(Cake)')]\n",
"\n",
"for action in solution:\n",
" cakeProblem.act(action)"
]
},
{
"cell_type": "markdown",
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"It raises an exception.\n",
"Indeed, according to the problem, we cannot bake a cake if we already have one.\n",
"In planning terms, '~Have(Cake)' is a precondition to the action 'Bake(Cake)'.\n",
"Hence, this solution is invalid."
]
},
{
"cell_type": "markdown",
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"source": [
"## SOLVING PLANNING PROBLEMS\n",
"----\n",
"### GRAPHPLAN\n",
"<br>\n",
"The GraphPlan algorithm is a popular method of solving classical planning problems.\n",
"Before we get into the details of the algorithm, let's look at a special data structure called **planning graph**, used to give better heuristic estimates and plays a key role in the GraphPlan algorithm."
]
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{
"cell_type": "markdown",
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"source": [
"### Planning Graph\n",
"A planning graph is a directed graph organized into levels. \n",
"Each level contains information about the current state of the knowledge base and the possible state-action links to and from that level.\n",
"The first level contains the initial state with nodes representing each fluent that holds in that level.\n",
"This level has state-action links linking each state to valid actions in that state.\n",
"Each action is linked to all its preconditions and its effect states.\n",
"Based on these effects, the next level is constructed.\n",
"The next level contains similarly structured information about the next state.\n",
"In this way, the graph is expanded using state-action links till we reach a state where all the required goals hold true simultaneously.\n",
"We can say that we have reached our goal if none of the goal states in the current level are mutually exclusive.\n",
"This will be explained in detail later.\n",
"<br>\n",
"Planning graphs only work for propositional planning problems, hence we need to eliminate all variables by generating all possible substitutions.\n",
"<br>\n",
"For example, the planning graph of the `have_cake_and_eat_cake_too` problem might look like this\n",
"\n",
"<br>\n",
"The black lines indicate links between states and actions.\n",
"<br>\n",
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"In every planning problem, we are allowed to carry out the `no-op` action, ie, we can choose no action for a particular state.\n",
"These are called 'Persistence' actions and are represented in the graph by the small square boxes.\n",
"In technical terms, a persistence action has effects same as its preconditions.\n",
"This enables us to carry a state to the next level.\n",
"<br>\n",
"<br>\n",
"The gray lines indicate mutual exclusivity.\n",
"This means that the actions connected bya gray line cannot be taken together.\n",
"Mutual exclusivity (mutex) occurs in the following cases:\n",
"1. **Inconsistent effects**: One action negates the effect of the other. For example, _Eat(Cake)_ and the persistence of _Have(Cake)_ have inconsistent effects because they disagree on the effect _Have(Cake)_\n",
"2. **Interference**: One of the effects of an action is the negation of a precondition of the other. For example, _Eat(Cake)_ interferes with the persistence of _Have(Cake)_ by negating its precondition.\n",
"3. **Competing needs**: One of the preconditions of one action is mutually exclusive with a precondition of the other. For example, _Bake(Cake)_ and _Eat(Cake)_ are mutex because they compete on the value of the _Have(Cake)_ precondition."
]
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"In the module, planning graphs have been implemented using two classes, `Level` which stores data for a particular level and `Graph` which connects multiple levels together.\n",
"Let's look at the `Level` class."
]
},
{
"cell_type": "code",
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"</head>\n",
"<body>\n",
"<h2></h2>\n",
"\n",
"<div class=\"highlight\"><pre><span></span><span class=\"k\">class</span> <span class=\"nc\">Level</span><span class=\"p\">:</span>\n",
" <span class=\"sd\">"""</span>\n",
"<span class=\"sd\"> Contains the state of the planning problem</span>\n",
"<span class=\"sd\"> and exhaustive list of actions which use the</span>\n",
"<span class=\"sd\"> states as pre-condition.</span>\n",
"<span class=\"sd\"> """</span>\n",
"\n",
" <span class=\"k\">def</span> <span class=\"fm\">__init__</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">,</span> <span class=\"n\">kb</span><span class=\"p\">):</span>\n",
" <span class=\"sd\">"""Initializes variables to hold state and action details of a level"""</span>\n",
"\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">kb</span> <span class=\"o\">=</span> <span class=\"n\">kb</span>\n",
" <span class=\"c1\"># current state</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state</span> <span class=\"o\">=</span> <span class=\"n\">kb</span><span class=\"o\">.</span><span class=\"n\">clauses</span>\n",
" <span class=\"c1\"># current action to state link</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_action_links</span> <span class=\"o\">=</span> <span class=\"p\">{}</span>\n",
" <span class=\"c1\"># current state to action link</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span> <span class=\"o\">=</span> <span class=\"p\">{}</span>\n",
" <span class=\"c1\"># current action to next state link</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_action_links</span> <span class=\"o\">=</span> <span class=\"p\">{}</span>\n",
" <span class=\"c1\"># next state to current action link</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span> <span class=\"o\">=</span> <span class=\"p\">{}</span>\n",
" <span class=\"c1\"># mutually exclusive actions</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n",
"\n",
" <span class=\"k\">def</span> <span class=\"fm\">__call__</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">,</span> <span class=\"n\">actions</span><span class=\"p\">,</span> <span class=\"n\">objects</span><span class=\"p\">):</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">build</span><span class=\"p\">(</span><span class=\"n\">actions</span><span class=\"p\">,</span> <span class=\"n\">objects</span><span class=\"p\">)</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">find_mutex</span><span class=\"p\">()</span>\n",
"\n",
" <span class=\"k\">def</span> <span class=\"nf\">separate</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">,</span> <span class=\"n\">e</span><span class=\"p\">):</span>\n",
" <span class=\"sd\">"""Separates an iterable of elements into positive and negative parts"""</span>\n",
"\n",
" <span class=\"n\">positive</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n",
" <span class=\"n\">negative</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">clause</span> <span class=\"ow\">in</span> <span class=\"n\">e</span><span class=\"p\">:</span>\n",
" <span class=\"k\">if</span> <span class=\"n\">clause</span><span class=\"o\">.</span><span class=\"n\">op</span><span class=\"p\">[:</span><span class=\"mi\">3</span><span class=\"p\">]</span> <span class=\"o\">==</span> <span class=\"s1\">'Not'</span><span class=\"p\">:</span>\n",
" <span class=\"n\">negative</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">clause</span><span class=\"p\">)</span>\n",
" <span class=\"k\">else</span><span class=\"p\">:</span>\n",
" <span class=\"n\">positive</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">clause</span><span class=\"p\">)</span>\n",
" <span class=\"k\">return</span> <span class=\"n\">positive</span><span class=\"p\">,</span> <span class=\"n\">negative</span>\n",
"\n",
" <span class=\"k\">def</span> <span class=\"nf\">find_mutex</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n",
" <span class=\"sd\">"""Finds mutually exclusive actions"""</span>\n",
"\n",
" <span class=\"c1\"># Inconsistent effects</span>\n",
" <span class=\"n\">pos_nsl</span><span class=\"p\">,</span> <span class=\"n\">neg_nsl</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">separate</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"p\">)</span>\n",
"\n",
" <span class=\"k\">for</span> <span class=\"n\">negeff</span> <span class=\"ow\">in</span> <span class=\"n\">neg_nsl</span><span class=\"p\">:</span>\n",
" <span class=\"n\">new_negeff</span> <span class=\"o\">=</span> <span class=\"n\">Expr</span><span class=\"p\">(</span><span class=\"n\">negeff</span><span class=\"o\">.</span><span class=\"n\">op</span><span class=\"p\">[</span><span class=\"mi\">3</span><span class=\"p\">:],</span> <span class=\"o\">*</span><span class=\"n\">negeff</span><span class=\"o\">.</span><span class=\"n\">args</span><span class=\"p\">)</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">poseff</span> <span class=\"ow\">in</span> <span class=\"n\">pos_nsl</span><span class=\"p\">:</span>\n",
" <span class=\"k\">if</span> <span class=\"n\">new_negeff</span> <span class=\"o\">==</span> <span class=\"n\">poseff</span><span class=\"p\">:</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">a</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"p\">[</span><span class=\"n\">poseff</span><span class=\"p\">]:</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">b</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"p\">[</span><span class=\"n\">negeff</span><span class=\"p\">]:</span>\n",
" <span class=\"k\">if</span> <span class=\"p\">{</span><span class=\"n\">a</span><span class=\"p\">,</span> <span class=\"n\">b</span><span class=\"p\">}</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span><span class=\"p\">:</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">({</span><span class=\"n\">a</span><span class=\"p\">,</span> <span class=\"n\">b</span><span class=\"p\">})</span>\n",
"\n",
" <span class=\"c1\"># Interference will be calculated with the last step</span>\n",
" <span class=\"n\">pos_csl</span><span class=\"p\">,</span> <span class=\"n\">neg_csl</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">separate</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span><span class=\"p\">)</span>\n",
"\n",
" <span class=\"c1\"># Competing needs</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">posprecond</span> <span class=\"ow\">in</span> <span class=\"n\">pos_csl</span><span class=\"p\">:</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">negprecond</span> <span class=\"ow\">in</span> <span class=\"n\">neg_csl</span><span class=\"p\">:</span>\n",
" <span class=\"n\">new_negprecond</span> <span class=\"o\">=</span> <span class=\"n\">Expr</span><span class=\"p\">(</span><span class=\"n\">negprecond</span><span class=\"o\">.</span><span class=\"n\">op</span><span class=\"p\">[</span><span class=\"mi\">3</span><span class=\"p\">:],</span> <span class=\"o\">*</span><span class=\"n\">negprecond</span><span class=\"o\">.</span><span class=\"n\">args</span><span class=\"p\">)</span>\n",
" <span class=\"k\">if</span> <span class=\"n\">new_negprecond</span> <span class=\"o\">==</span> <span class=\"n\">posprecond</span><span class=\"p\">:</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">a</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span><span class=\"p\">[</span><span class=\"n\">posprecond</span><span class=\"p\">]:</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">b</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span><span class=\"p\">[</span><span class=\"n\">negprecond</span><span class=\"p\">]:</span>\n",
" <span class=\"k\">if</span> <span class=\"p\">{</span><span class=\"n\">a</span><span class=\"p\">,</span> <span class=\"n\">b</span><span class=\"p\">}</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span><span class=\"p\">:</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">({</span><span class=\"n\">a</span><span class=\"p\">,</span> <span class=\"n\">b</span><span class=\"p\">})</span>\n",
"\n",
" <span class=\"c1\"># Inconsistent support</span>\n",
" <span class=\"n\">state_mutex</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">pair</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span><span class=\"p\">:</span>\n",
" <span class=\"n\">next_state_0</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_action_links</span><span class=\"p\">[</span><span class=\"nb\">list</span><span class=\"p\">(</span><span class=\"n\">pair</span><span class=\"p\">)[</span><span class=\"mi\">0</span><span class=\"p\">]]</span>\n",
" <span class=\"k\">if</span> <span class=\"nb\">len</span><span class=\"p\">(</span><span class=\"n\">pair</span><span class=\"p\">)</span> <span class=\"o\">==</span> <span class=\"mi\">2</span><span class=\"p\">:</span>\n",
" <span class=\"n\">next_state_1</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_action_links</span><span class=\"p\">[</span><span class=\"nb\">list</span><span class=\"p\">(</span><span class=\"n\">pair</span><span class=\"p\">)[</span><span class=\"mi\">1</span><span class=\"p\">]]</span>\n",
" <span class=\"k\">else</span><span class=\"p\">:</span>\n",
" <span class=\"n\">next_state_1</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_action_links</span><span class=\"p\">[</span><span class=\"nb\">list</span><span class=\"p\">(</span><span class=\"n\">pair</span><span class=\"p\">)[</span><span class=\"mi\">0</span><span class=\"p\">]]</span>\n",
" <span class=\"k\">if</span> <span class=\"p\">(</span><span class=\"nb\">len</span><span class=\"p\">(</span><span class=\"n\">next_state_0</span><span class=\"p\">)</span> <span class=\"o\">==</span> <span class=\"mi\">1</span><span class=\"p\">)</span> <span class=\"ow\">and</span> <span class=\"p\">(</span><span class=\"nb\">len</span><span class=\"p\">(</span><span class=\"n\">next_state_1</span><span class=\"p\">)</span> <span class=\"o\">==</span> <span class=\"mi\">1</span><span class=\"p\">):</span>\n",
" <span class=\"n\">state_mutex</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">({</span><span class=\"n\">next_state_0</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">],</span> <span class=\"n\">next_state_1</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]})</span>\n",
" \n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">mutex</span> <span class=\"o\">+</span> <span class=\"n\">state_mutex</span>\n",
"\n",
" <span class=\"k\">def</span> <span class=\"nf\">build</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">,</span> <span class=\"n\">actions</span><span class=\"p\">,</span> <span class=\"n\">objects</span><span class=\"p\">):</span>\n",
" <span class=\"sd\">"""Populates the lists and dictionaries containing the state action dependencies"""</span>\n",
"\n",
" <span class=\"k\">for</span> <span class=\"n\">clause</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state</span><span class=\"p\">:</span>\n",
" <span class=\"n\">p_expr</span> <span class=\"o\">=</span> <span class=\"n\">Expr</span><span class=\"p\">(</span><span class=\"s1\">'P'</span> <span class=\"o\">+</span> <span class=\"n\">clause</span><span class=\"o\">.</span><span class=\"n\">op</span><span class=\"p\">,</span> <span class=\"o\">*</span><span class=\"n\">clause</span><span class=\"o\">.</span><span class=\"n\">args</span><span class=\"p\">)</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_action_links</span><span class=\"p\">[</span><span class=\"n\">p_expr</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[</span><span class=\"n\">clause</span><span class=\"p\">]</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_action_links</span><span class=\"p\">[</span><span class=\"n\">p_expr</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[</span><span class=\"n\">clause</span><span class=\"p\">]</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span><span class=\"p\">[</span><span class=\"n\">clause</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[</span><span class=\"n\">p_expr</span><span class=\"p\">]</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"p\">[</span><span class=\"n\">clause</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[</span><span class=\"n\">p_expr</span><span class=\"p\">]</span>\n",
"\n",
" <span class=\"k\">for</span> <span class=\"n\">a</span> <span class=\"ow\">in</span> <span class=\"n\">actions</span><span class=\"p\">:</span>\n",
" <span class=\"n\">num_args</span> <span class=\"o\">=</span> <span class=\"nb\">len</span><span class=\"p\">(</span><span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">args</span><span class=\"p\">)</span>\n",
" <span class=\"n\">possible_args</span> <span class=\"o\">=</span> <span class=\"nb\">tuple</span><span class=\"p\">(</span><span class=\"n\">itertools</span><span class=\"o\">.</span><span class=\"n\">permutations</span><span class=\"p\">(</span><span class=\"n\">objects</span><span class=\"p\">,</span> <span class=\"n\">num_args</span><span class=\"p\">))</span>\n",
"\n",
" <span class=\"k\">for</span> <span class=\"n\">arg</span> <span class=\"ow\">in</span> <span class=\"n\">possible_args</span><span class=\"p\">:</span>\n",
" <span class=\"k\">if</span> <span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">check_precond</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">kb</span><span class=\"p\">,</span> <span class=\"n\">arg</span><span class=\"p\">):</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">num</span><span class=\"p\">,</span> <span class=\"n\">symbol</span> <span class=\"ow\">in</span> <span class=\"nb\">enumerate</span><span class=\"p\">(</span><span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">args</span><span class=\"p\">):</span>\n",
" <span class=\"k\">if</span> <span class=\"ow\">not</span> <span class=\"n\">symbol</span><span class=\"o\">.</span><span class=\"n\">op</span><span class=\"o\">.</span><span class=\"n\">islower</span><span class=\"p\">():</span>\n",
" <span class=\"n\">arg</span> <span class=\"o\">=</span> <span class=\"nb\">list</span><span class=\"p\">(</span><span class=\"n\">arg</span><span class=\"p\">)</span>\n",
" <span class=\"n\">arg</span><span class=\"p\">[</span><span class=\"n\">num</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"n\">symbol</span>\n",
" <span class=\"n\">arg</span> <span class=\"o\">=</span> <span class=\"nb\">tuple</span><span class=\"p\">(</span><span class=\"n\">arg</span><span class=\"p\">)</span>\n",
"\n",
" <span class=\"n\">new_action</span> <span class=\"o\">=</span> <span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">substitute</span><span class=\"p\">(</span><span class=\"n\">Expr</span><span class=\"p\">(</span><span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">name</span><span class=\"p\">,</span> <span class=\"o\">*</span><span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">args</span><span class=\"p\">),</span> <span class=\"n\">arg</span><span class=\"p\">)</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_action_links</span><span class=\"p\">[</span><span class=\"n\">new_action</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n",
"\n",
" <span class=\"k\">for</span> <span class=\"n\">clause</span> <span class=\"ow\">in</span> <span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">precond</span><span class=\"p\">:</span>\n",
" <span class=\"n\">new_clause</span> <span class=\"o\">=</span> <span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">substitute</span><span class=\"p\">(</span><span class=\"n\">clause</span><span class=\"p\">,</span> <span class=\"n\">arg</span><span class=\"p\">)</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_action_links</span><span class=\"p\">[</span><span class=\"n\">new_action</span><span class=\"p\">]</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_clause</span><span class=\"p\">)</span>\n",
" <span class=\"k\">if</span> <span class=\"n\">new_clause</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span><span class=\"p\">:</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span><span class=\"p\">[</span><span class=\"n\">new_clause</span><span class=\"p\">]</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_action</span><span class=\"p\">)</span>\n",
" <span class=\"k\">else</span><span class=\"p\">:</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">current_state_links</span><span class=\"p\">[</span><span class=\"n\">new_clause</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[</span><span class=\"n\">new_action</span><span class=\"p\">]</span>\n",
" \n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_action_links</span><span class=\"p\">[</span><span class=\"n\">new_action</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n",
" <span class=\"k\">for</span> <span class=\"n\">clause</span> <span class=\"ow\">in</span> <span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">effect</span><span class=\"p\">:</span>\n",
" <span class=\"n\">new_clause</span> <span class=\"o\">=</span> <span class=\"n\">a</span><span class=\"o\">.</span><span class=\"n\">substitute</span><span class=\"p\">(</span><span class=\"n\">clause</span><span class=\"p\">,</span> <span class=\"n\">arg</span><span class=\"p\">)</span>\n",
"\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_action_links</span><span class=\"p\">[</span><span class=\"n\">new_action</span><span class=\"p\">]</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_clause</span><span class=\"p\">)</span>\n",
" <span class=\"k\">if</span> <span class=\"n\">new_clause</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"p\">:</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"p\">[</span><span class=\"n\">new_clause</span><span class=\"p\">]</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_action</span><span class=\"p\">)</span>\n",
" <span class=\"k\">else</span><span class=\"p\">:</span>\n",
" <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"p\">[</span><span class=\"n\">new_clause</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"p\">[</span><span class=\"n\">new_action</span><span class=\"p\">]</span>\n",
"\n",
" <span class=\"k\">def</span> <span class=\"nf\">perform_actions</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n",
" <span class=\"sd\">"""Performs the necessary actions and returns a new Level"""</span>\n",
"\n",
" <span class=\"n\">new_kb</span> <span class=\"o\">=</span> <span class=\"n\">FolKB</span><span class=\"p\">(</span><span class=\"nb\">list</span><span class=\"p\">(</span><span class=\"nb\">set</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">next_state_links</span><span class=\"o\">.</span><span class=\"n\">keys</span><span class=\"p\">())))</span>\n",
" <span class=\"k\">return</span> <span class=\"n\">Level</span><span class=\"p\">(</span><span class=\"n\">new_kb</span><span class=\"p\">)</span>\n",