multidimensional_example.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import sys
import os
import pandas as pd


def main(argc, argv):
    from amplpy import AMPL, DataFrame

    os.chdir(os.path.dirname(__file__) or os.curdir)

    """
    # If you are not using amplpy.modules, and the AMPL installation directory
    # is not in the system search path, add it as follows:
    from amplpy import add_to_path
    add_to_path(r"full path to the AMPL installation directory")
    """

    # Create an AMPL instance
    ampl = AMPL()

    ampl.eval("set CITIES; set LINKS within (CITIES cross CITIES);")
    ampl.eval("param cost {LINKS} >= 0; param capacity {LINKS} >= 0;")
    ampl.eval("data; set CITIES := PITT NE SE BOS EWR BWI ATL MCO;")

    # Using a pandas.DataFrame:
    df = pd.DataFrame(
        {
            "LINKSFrom": ["PITT", "PITT", "NE", "NE", "NE", "SE", "SE", "SE", "SE"],
            "LINKSTo": ["NE", "SE", "BOS", "EWR", "BWI", "EWR", "BWI", "ATL", "MCO"],
            "cost": [2.5, 3.5, 1.7, 0.7, 1.3, 1.3, 0.8, 0.2, 2.1],
            "capacity": [250, 250, 100, 100, 100, 100, 100, 100, 100],
        }
    ).set_index(["LINKSFrom", "LINKSTo"])
    print(df)

    ampl.eval("reset data LINKS;")
    ampl.set_data(df, "LINKS")
    ampl.display("LINKS")


if __name__ == "__main__":
    try:
        main(len(sys.argv), sys.argv)
    except Exception as e:
        print(e)
        raise