202 lines
6.6 KiB
Plaintext
202 lines
6.6 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"id": "google",
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"metadata": {},
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"source": [
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"##### Copyright 2022 Google LLC."
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]
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},
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{
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"cell_type": "markdown",
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"id": "apache",
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"metadata": {},
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"source": [
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"Licensed under the Apache License, Version 2.0 (the \"License\");\n",
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"you may not use this file except in compliance with the License.\n",
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"You may obtain a copy of the License at\n",
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"\n",
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" http://www.apache.org/licenses/LICENSE-2.0\n",
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"\n",
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"Unless required by applicable law or agreed to in writing, software\n",
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"distributed under the License is distributed on an \"AS IS\" BASIS,\n",
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"WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n",
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"See the License for the specific language governing permissions and\n",
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"limitations under the License.\n"
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]
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},
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{
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"cell_type": "markdown",
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"id": "basename",
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"metadata": {},
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"source": [
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"# integer_programming"
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]
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},
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{
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"cell_type": "markdown",
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"id": "link",
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"metadata": {},
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"source": [
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"<table align=\"left\">\n",
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"<td>\n",
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"<a href=\"https://colab.research.google.com/github/google/or-tools/blob/main/examples/notebook/examples/integer_programming.ipynb\"><img src=\"https://raw.githubusercontent.com/google/or-tools/main/tools/colab_32px.png\"/>Run in Google Colab</a>\n",
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"</td>\n",
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"<td>\n",
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"<a href=\"https://github.com/google/or-tools/blob/main/examples/python/integer_programming.py\"><img src=\"https://raw.githubusercontent.com/google/or-tools/main/tools/github_32px.png\"/>View source on GitHub</a>\n",
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"</td>\n",
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"</table>"
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]
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},
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{
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"cell_type": "markdown",
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"id": "doc",
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"metadata": {},
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"source": [
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"First, you must install [ortools](https://pypi.org/project/ortools/) package in this colab."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "install",
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"metadata": {},
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"outputs": [],
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"source": [
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"!pip install ortools"
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]
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},
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{
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"cell_type": "markdown",
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"id": "description",
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"metadata": {},
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"source": [
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"Integer programming examples that show how to use the APIs.\n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "code",
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"metadata": {},
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"outputs": [],
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"source": [
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"from ortools.linear_solver import pywraplp\n",
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"from ortools.init import pywrapinit\n",
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"\n",
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"\n",
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"def Announce(solver, api_type):\n",
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" print('---- Integer programming example with ' + solver + ' (' + api_type +\n",
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" ') -----')\n",
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"\n",
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"\n",
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"def RunIntegerExampleNaturalLanguageAPI(optimization_problem_type):\n",
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" \"\"\"Example of simple integer program with natural language API.\"\"\"\n",
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"\n",
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" solver = pywraplp.Solver.CreateSolver(optimization_problem_type)\n",
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" if not solver:\n",
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" return\n",
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"\n",
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" Announce(optimization_problem_type, 'natural language API')\n",
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"\n",
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" infinity = solver.infinity()\n",
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" # x1 and x2 are integer non-negative variables.\n",
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" x1 = solver.IntVar(0.0, infinity, 'x1')\n",
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" x2 = solver.IntVar(0.0, infinity, 'x2')\n",
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"\n",
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" solver.Minimize(x1 + 2 * x2)\n",
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" solver.Add(3 * x1 + 2 * x2 >= 17)\n",
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"\n",
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" SolveAndPrint(solver, [x1, x2])\n",
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"\n",
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"\n",
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"def RunIntegerExampleCppStyleAPI(optimization_problem_type):\n",
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" \"\"\"Example of simple integer program with the C++ style API.\"\"\"\n",
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" solver = pywraplp.Solver.CreateSolver(optimization_problem_type)\n",
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" if not solver:\n",
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" return\n",
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"\n",
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" Announce(optimization_problem_type, 'C++ style API')\n",
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"\n",
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" infinity = solver.infinity()\n",
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" # x1 and x2 are integer non-negative variables.\n",
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" x1 = solver.IntVar(0.0, infinity, 'x1')\n",
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" x2 = solver.IntVar(0.0, infinity, 'x2')\n",
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"\n",
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" # Minimize x1 + 2 * x2.\n",
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" objective = solver.Objective()\n",
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" objective.SetCoefficient(x1, 1)\n",
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" objective.SetCoefficient(x2, 2)\n",
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"\n",
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" # 2 * x2 + 3 * x1 >= 17.\n",
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" ct = solver.Constraint(17, infinity)\n",
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" ct.SetCoefficient(x1, 3)\n",
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" ct.SetCoefficient(x2, 2)\n",
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"\n",
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" SolveAndPrint(solver, [x1, x2])\n",
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"\n",
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"\n",
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"def SolveAndPrint(solver, variable_list):\n",
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" \"\"\"Solve the problem and print the solution.\"\"\"\n",
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" print('Number of variables = %d' % solver.NumVariables())\n",
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" print('Number of constraints = %d' % solver.NumConstraints())\n",
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"\n",
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" result_status = solver.Solve()\n",
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"\n",
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" # The problem has an optimal solution.\n",
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" assert result_status == pywraplp.Solver.OPTIMAL\n",
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"\n",
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" # The solution looks legit (when using solvers others than\n",
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" # GLOP_LINEAR_PROGRAMMING, verifying the solution is highly recommended!).\n",
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" assert solver.VerifySolution(1e-7, True)\n",
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"\n",
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" print('Problem solved in %f milliseconds' % solver.wall_time())\n",
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"\n",
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" # The objective value of the solution.\n",
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" print('Optimal objective value = %f' % solver.Objective().Value())\n",
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"\n",
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" # The value of each variable in the solution.\n",
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" for variable in variable_list:\n",
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" print('%s = %f' % (variable.name(), variable.solution_value()))\n",
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"\n",
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" print('Advanced usage:')\n",
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" print('Problem solved in %d branch-and-bound nodes' % solver.nodes())\n",
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"\n",
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"\n",
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"def RunAllIntegerExampleNaturalLanguageAPI():\n",
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" RunIntegerExampleNaturalLanguageAPI('GLPK')\n",
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" RunIntegerExampleNaturalLanguageAPI('CBC')\n",
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" RunIntegerExampleNaturalLanguageAPI('SCIP')\n",
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" RunIntegerExampleNaturalLanguageAPI('SAT')\n",
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" RunIntegerExampleNaturalLanguageAPI('Gurobi')\n",
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"\n",
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"\n",
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"def RunAllIntegerExampleCppStyleAPI():\n",
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" RunIntegerExampleCppStyleAPI('GLPK')\n",
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" RunIntegerExampleCppStyleAPI('CBC')\n",
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" RunIntegerExampleCppStyleAPI('SCIP')\n",
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" RunIntegerExampleCppStyleAPI('SAT')\n",
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" RunIntegerExampleCppStyleAPI('Gurobi')\n",
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"\n",
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"\n",
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"def main():\n",
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" RunAllIntegerExampleNaturalLanguageAPI()\n",
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" RunAllIntegerExampleCppStyleAPI()\n",
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"\n",
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"\n",
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"pywrapinit.CppBridge.InitLogging('integer_programming.py')\n",
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"cpp_flags = pywrapinit.CppFlags()\n",
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"cpp_flags.logtostderr = True\n",
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"cpp_flags.log_prefix = False\n",
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"pywrapinit.CppBridge.SetFlags(cpp_flags)\n",
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"main()\n",
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"\n"
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]
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}
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],
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"metadata": {},
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"nbformat": 4,
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"nbformat_minor": 5
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}
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