autoSolver.py

from __future__ import print_function
from numpy import *
from ortools.graph import pywrapgraph
import time

infinite = 10000000
price = 1

def main():

    counter = 0 #how many were successful

    #Change these parameters
    halfDays = 2
    segments = 4 #I've defined segment to be the number of time slots between cycles, so there are 2*segment intervals in a day
    nodes = 5
    initialBikes = 50 #total number of starting bikes
    maxMovement = 3
    numberOfTrials = 1000

    startTime = time.time()
    for trial in range(0, numberOfTrials):
        if( trial % 100 == 0):
            print("Trial: " + str(trial))

        startingBikes = full((nodes), 0)
        for i in range(initialBikes):
            startingBikes[random.randint(0, nodes)] += 1
        totalBikes = sum(startingBikes)

        bikeData = random.random_integers(0, maxMovement, size=(segments*halfDays, nodes, nodes))
        for i in range (0, segments*halfDays):
            for j in range (0, nodes):
                bikeData[i][j][j] = 0

        inBikes = sum(bikeData, axis=1)

        min_cost_flow = pywrapgraph.SimpleMinCostFlow()

        start(min_cost_flow, nodes, startingBikes)
        offset = nodes
        for i in range(0, segments*halfDays):
            if(i % segments == 0):
                costCycle(min_cost_flow, nodes, offset)
                offset = offset + nodes
            freeCycle(min_cost_flow, nodes, offset, i, bikeData, inBikes)
            offset = offset + 2 * nodes
        end(min_cost_flow, nodes, offset, totalBikes)


        if min_cost_flow.Solve() == min_cost_flow.OPTIMAL:
            counter = counter + 1

    endTime = time.time()
    print('Runtime per trial: ' + str((endTime - startTime) / numberOfTrials))
    print('Finished\n %1s / %2s successful' % (counter, numberOfTrials))


def start(graph, size, data):
    # print("\nStarting start")
    for i in range(0, size):
        # print('Node %1s with supply %2s' % (i, data[i]))
        graph.SetNodeSupply(i, data[i])

def freeCycle(graph, size, offset, time, data, sumData):
    # print("\nStarting freeCycle")
    for i in range(0, size):
        # print('Node %1s with supply %2s' % ( offset+i, -1*sumData[time][i]))
        graph.SetNodeSupply(offset+i, -1*sumData[time][i].item())
        # print('Node %1s with supply %2s' % ( offset+i+size, sumData[time][i]))
        graph.SetNodeSupply(offset+i+size, sumData[time][i].item())
        # print('Node %1s with supply %2s' % ( offset+i+2*size, 0))
        # graph.SetNodeSupply(offset+i+2*size, 0)

        # print('Arc from %1s to %2s with capacity %3s and cost %4s' % (offset - size + i, offset + i + size, infinite, 0))
        graph.AddArcWithCapacityAndUnitCost(offset - size + i, offset + i + size, infinite, 0)

        for j in range (0, size):
            if(j != i):
                # print('Arc from %1s to %2s with capacity %3s and cost %4s' % (offset + i - size, offset + j, data[time][i][j], 0))
                graph.AddArcWithCapacityAndUnitCost(offset + i - size, offset + j, data[time][i][j].item(), 0)

        # print('Arc from %1s to %2s with capacity %3s and cost %4s' % (i + offset + size, i + offset + 2*size, infinite, 0))
        # graph.AddArcWithCapacityAndUnitCost(i + offset + size, i + offset + 2*size, infinite, 0)

def costCycle(graph, size, offset):
    # print("\nStarting cost cycle")
    for i in range(0, size):
        # print('Node %1s with supply %2s' % ( offset+i, 0))
        graph.SetNodeSupply(offset+i, 0)
        for j in range(0, size):
            if(i == j):
                # print('Arc from %1s to %2s with capacity %3s and cost %4s' % (offset - size + i, offset + j, infinite, 0))
                graph.AddArcWithCapacityAndUnitCost(offset - size + i, offset + j, infinite, 0)
            else:
                # print('Arc from %1s to %2s with capacity %3s and cost %4s' % (offset - size + i, offset + j, infinite, price))
                graph.AddArcWithCapacityAndUnitCost(offset - size + i, offset + j, infinite, price)

def end(graph, size, offset, totalBikes):
    # print("\nStarting end")
    graph.SetNodeSupply(offset, -1* totalBikes.item())
    for i in range(0, size):
        # print('Arc from %1s to %2s with capacity %3s and cost %4s' % (offset + i - size, offset, infinite, 0))
        graph.AddArcWithCapacityAndUnitCost(offset + i - size, offset, infinite, 0)

if __name__ == '__main__':
  main()