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+{
+ "cells": [
+ {
+ "cell_type": "markdown",
+ "id": "9eb5530a",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "source": [
+ "Empty Prolog Notebook"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "id": "40ad6905",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [],
+ "source": [
+ ":- consult('prolog_files/roumania.pl')."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 2,
+ "id": "9c7e889c",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mDist = 75,\n",
+ "City = zerind"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "?- s(arad,Dist,City)."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 5,
+ "id": "af6a9e4a",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/markdown": [
+ "Dist | City | \n",
+ ":- | :- | \n",
+ "75 | zerind | \n",
+ "118 | timisoara | \n",
+ "140 | sibiu | "
+ ],
+ "text/plain": [
+ "Dist | City | \n",
+ ":- | :- | \n",
+ "75 | zerind | \n",
+ "118 | timisoara | \n",
+ "140 | sibiu | "
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mtrue"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "jupyter:print_table(s(arad,Dist,City))"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 6,
+ "id": "55da475c",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/markdown": [
+ "City | Dist | \n",
+ ":- | :- | \n",
+ "zerind | 75 | \n",
+ "timisoara | 118 | \n",
+ "sibiu | 140 | "
+ ],
+ "text/plain": [
+ "City | Dist | \n",
+ ":- | :- | \n",
+ "zerind | 75 | \n",
+ "timisoara | 118 | \n",
+ "sibiu | 140 | "
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mtrue"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "jupyter:print_table(wkante(City,Dist,arad))"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 7,
+ "id": "c32206c4",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mSLDZ = 374,\n",
+ "SLDT = 329,\n",
+ "SLDS = 253"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "?- h(zerind,SLDZ), h(timisoara,SLDT), h(sibiu,SLDS)."
+ ]
+ },
+ {
+ "attachments": {},
+ "cell_type": "markdown",
+ "id": "3e904005",
+ "metadata": {},
+ "source": [
+ "The following is the evaluation function we will use in the A* algorithm:"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 8,
+ "id": "e942f0d4",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [],
+ "source": [
+ "eval_function(G_SoFar,H_EstDist,F) :- F is G_SoFar+H_EstDist. % A*\n",
+ "%eval_function(_G_SoFar,H_EstDist,F) :- F =H_EstDist. % Greedy\n",
+ "%eval_function(G_SoFar,_,F) :- F=G_SoFar. % Dijkstra"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 11,
+ "id": "242f4141",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mHZerind = 449,\n",
+ "HSibiu = 393,\n",
+ "HTimisoara = 447"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "?- eval_function(75,374,HZerind), eval_function(140,253,HSibiu),\n",
+ " eval_function(118,329,HTimisoara)."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 12,
+ "id": "78764141",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [],
+ "source": [
+ "\n",
+ ":- use_module(library(heaps)).\n",
+ "\n",
+ "add_states_to_heap([],H,H).\n",
+ "add_states_to_heap([st(G,State)|T],Heap,UpdHeap) :-\n",
+ " (h(State,SH) -> true ; print(err(State)),nl,SH=1000), % compute heuristic function\n",
+ " eval_function(G,SH,F), % Compute weight\n",
+ " add_to_heap(Heap,F,st(G,State),H2),\n",
+ " add_states_to_heap(T,H2,UpdHeap)."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 15,
+ "id": "b03ac6e7",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ " A* Heap = [393-st(140,sibiu),447-st(118,timisoara),449-st(75,zerind)]"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mEH = heap(nil,0),\n",
+ "NewHeap = heap(t(st(140,sibiu),393,[t(st(118,timisoara),447,[]),t(st(75,zerind),449,[])]),3),\n",
+ "List = [393-st(140,sibiu),447-st(118,timisoara),449-st(75,zerind)]"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "?- empty_heap(EH), add_states_to_heap([st(75,zerind),st(140,sibiu),st(118,timisoara)],EH,NewHeap),\n",
+ " heap_to_list(NewHeap,List), format(' A* Heap = ~w~n',[List])."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 16,
+ "id": "f6f156a3",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [],
+ "source": [
+ "astar :- statistics(runtime,_),start(S), \n",
+ " astar(S), \n",
+ " statistics(runtime,[_,T]), print(T),print(' ms'),nl.\n",
+ "\n",
+ "astar(S) :- empty_heap(EH),\n",
+ " add_states_to_heap([st(0,S)],EH,StartHeap),\n",
+ " nl,print('Starting A* search'),nl, \n",
+ " asearch(StartHeap,1).\n",
+ "\n",
+ "asearch(Heap,StepNr) :- \n",
+ " heap_to_list(Heap,List), format(' ~w: A* Heap = ~w~n',[StepNr,List]),\n",
+ " get_from_heap(Heap,_Heuristic,st(G,State),NewHeap),\n",
+ " %print(StepNr),print(' ==> '), print(st(G,State)),nl,\n",
+ " process_node(G,State,NewHeap,StepNr).\n",
+ "\n",
+ "% process_node(DistanceFromStart,State, Heap, StepNr)\n",
+ "process_node(G,State,_,StepNr) :-\n",
+ " ziel(State),\n",
+ " format('GOAL found at step ~w with distance ~w : ~w~n',[StepNr,G,State]).\n",
+ "process_node(G,State,Heap,StepNr) :-\n",
+ " findall(st(G1,SuccState),\n",
+ "\t (wkante(State,Weight,SuccState),G1 is G+Weight),SList),\n",
+ "\t% print(succs(SList)),nl,\n",
+ " add_states_to_heap(SList,Heap,UpdatedHeap),\n",
+ " S1 is StepNr+1,\n",
+ " asearch(UpdatedHeap,S1)."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 17,
+ "id": "9639129f",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "\n",
+ "'Starting A* search'\n",
+ " 1: A* Heap = [366-st(0,arad)]\n",
+ " 2: A* Heap = [393-st(140,sibiu),447-st(118,timisoara),449-st(75,zerind)]\n",
+ " 3: A* Heap = [413-st(220,rimnicu_vilcea),417-st(239,fagaras),447-st(118,timisoara),449-st(75,zerind),646-st(280,arad),671-st(291,oradea)]\n",
+ " 4: A* Heap = [415-st(317,pitesti),417-st(239,fagaras),447-st(118,timisoara),449-st(75,zerind),526-st(366,craiova),553-st(300,sibiu),646-st(280,arad),671-st(291,oradea)]\n",
+ " 5: A* Heap = [417-st(239,fagaras),418-st(418,bucharest),447-st(118,timisoara),449-st(75,zerind),526-st(366,craiova),553-st(300,sibiu),607-st(414,rimnicu_vilcea),615-st(455,craiova),646-st(280,arad),671-st(291,oradea)]\n",
+ " 6: A* Heap = [418-st(418,bucharest),447-st(118,timisoara),449-st(75,zerind),450-st(450,bucharest),526-st(366,craiova),553-st(300,sibiu),591-st(338,sibiu),607-st(414,rimnicu_vilcea),615-st(455,craiova),646-st(280,arad),671-st(291,oradea)]\n",
+ "GOAL found at step 6 with distance 418 : bucharest\n",
+ "0' ms'"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mtrue"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "?-astar."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 18,
+ "id": "943a1e1c",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [],
+ "source": [
+ "eval_function(_G_SoFar,H_EstDist,F) :- F =H_EstDist. % Greedy"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 19,
+ "id": "dab9377c",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "\n",
+ "'Starting A* search'\n",
+ " 1: A* Heap = [366-st(0,arad)]\n",
+ " 2: A* Heap = [253-st(140,sibiu),329-st(118,timisoara),374-st(75,zerind)]\n",
+ " 3: A* Heap = [178-st(239,fagaras),193-st(220,rimnicu_vilcea),329-st(118,timisoara),366-st(280,arad),374-st(75,zerind),380-st(291,oradea)]\n",
+ " 4: A* Heap = [0-st(450,bucharest),193-st(220,rimnicu_vilcea),253-st(338,sibiu),329-st(118,timisoara),366-st(280,arad),374-st(75,zerind),380-st(291,oradea)]\n",
+ "GOAL found at step 4 with distance 450 : bucharest\n",
+ "0' ms'"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "data": {
+ "text/plain": [
+ "\u001b[1mtrue"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "?-astar."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "ad76945b",
+ "metadata": {
+ "vscode": {
+ "languageId": "prolog"
+ }
+ },
+ "outputs": [],
+ "source": []
+ }
+ ],
+ "metadata": {
+ "kernelspec": {
+ "display_name": "Prolog",
+ "language": "prolog",
+ "name": "prolog_kernel"
+ },
+ "language_info": {
+ "codemirror_mode": "prolog",
+ "file_extension": ".pl",
+ "mimetype": "text/x-prolog",
+ "name": "Prolog"
+ }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}