edu.oregonstate.eecs.mcplan.domains.inventory.InventorySimulator.java Source code

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/* LICENSE
Copyright (c) 2013-2016, Jesse Hostetler (jessehostetler@gmail.com)
All rights reserved.
    
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    
1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
    
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/**
 * 
 */
package edu.oregonstate.eecs.mcplan.domains.inventory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Deque;

import org.apache.commons.math3.distribution.BinomialDistribution;
import org.apache.commons.math3.random.MersenneTwister;
import org.apache.commons.math3.random.RandomGenerator;

import edu.oregonstate.eecs.mcplan.JointAction;
import edu.oregonstate.eecs.mcplan.sim.UndoSimulator;
import edu.oregonstate.eecs.mcplan.util.Fn;
import gnu.trove.stack.TDoubleStack;
import gnu.trove.stack.array.TDoubleArrayStack;

/**
 * @author jhostetler
 *
 */
public class InventorySimulator implements UndoSimulator<InventoryState, InventoryAction> {
    public static final class DynamicsAction extends InventoryAction {
        private double old_r = 0;
        private boolean done = false;

        //      private int[] supplied = null;
        //      private int[] arrivals = null;
        private int[] old_inventory = null;
        private int[] old_orders = null;
        private int[] old_demand = null;

        @Override
        public DynamicsAction create() {
            return new DynamicsAction();
        }

        @Override
        public double reward() {
            return 0;
        }

        @Override
        public void undoAction(final InventoryState s) {
            assert (done);
            s.r = old_r;
            Fn.memcpy(s.inventory, old_inventory);
            Fn.memcpy(s.orders, old_orders);
            Fn.memcpy(s.demand, old_demand);

            old_r = 0;
            old_inventory = old_orders = old_demand = null;
        }

        @Override
        public void doAction(final RandomGenerator rng, final InventoryState s) {
            assert (!done);

            //         supplied = new int[s.problem.Nproducts];
            //         arrivals = new int[s.problem.Nproducts];

            old_inventory = Fn.copy(s.inventory);
            old_orders = Fn.copy(s.orders);
            old_demand = Fn.copy(s.demand);
            old_r = s.r;

            applyDynamics(s);

            done = true;
        }

        @Override
        public boolean isDone() {
            return done;
        }
    }

    public static void applyDynamics(final InventoryState s) {
        s.r = 0;
        for (int i = 0; i < s.problem.Nproducts; ++i) {
            // Pending orders arrive
            final BinomialDistribution f = new BinomialDistribution(s.orders[i], s.problem.delivery_probability);
            final int arrivals = f.sample();
            //         System.out.println( "\tarrivals[" + i + "] = " + arrivals );
            s.orders[i] -= arrivals;
            s.inventory[i] += arrivals;

            // Demand is satisfied
            final int supplied = Math.min(s.demand[i], s.inventory[i]);
            s.inventory[i] -= supplied;
            s.r += s.problem.price[i] * supplied;

            // Excess inventory is wasted
            s.inventory[i] = Math.min(s.inventory[i], s.problem.max_inventory);

            // Warehouse cost
            s.r -= s.inventory[i] * s.problem.warehouse_cost;

            // Demand changes
            //         s.demand[i] = s.rng.nextInt( s.problem.max_demand + 1 );
        }

        // Demand changes
        final int[] new_demand = s.problem.sampleNextDemand(s);
        Fn.memcpy(s.demand, new_demand);
    }

    private final InventoryState s;

    private final Deque<InventoryAction> history = new ArrayDeque<InventoryAction>();
    private final TDoubleStack rewards = new TDoubleArrayStack();
    private final int Nevents = 2;

    public InventorySimulator(final InventoryState s) {
        this.s = s;
        rewards.push(0);
    }

    @Override
    public InventoryState state() {
        return s;
    }

    @Override
    public void takeAction(final JointAction<InventoryAction> a) {
        final InventoryAction ai = a.get(0);
        ai.doAction(s);
        history.push(ai);

        final DynamicsAction d = new DynamicsAction();
        d.doAction(s);
        history.push(d);

        rewards.push(ai.reward() + d.reward());
    }

    @Override
    public long depth() {
        return history.size();
    }

    @Override
    public long t() {
        return history.size() / Nevents;
    }

    @Override
    public int nagents() {
        return 1;
    }

    @Override
    public int[] turn() {
        return new int[] { 0 };
    }

    @Override
    public double[] reward() {
        return new double[] { rewards.peek() };
    }

    @Override
    public boolean isTerminalState() {
        return s.isTerminal();
    }

    @Override
    public long horizon() {
        return Long.MAX_VALUE;
    }

    @Override
    public String detailString() {
        return "InventorySimulator";
    }

    @Override
    public void untakeLastAction() {
        for (int i = 0; i < Nevents; ++i) {
            history.pop().undoAction(s);
        }
        rewards.pop();
    }

    // -----------------------------------------------------------------------

    public static void main(final String[] argv) throws IOException {
        final RandomGenerator rng = new MersenneTwister(42);
        final int Nproducts = 2;
        final int max_inventory = 10;
        final double warehouse_cost = 1;
        final int min_order = 1;
        final int max_order = 2;
        final double delivery_probability = 0.5;
        final int max_demand = 5;
        final int[] price = new int[] { 1, 2 };

        final InventoryProblem problem = InventoryProblem.TwoProducts();
        //         Nproducts, price, max_inventory, warehouse_cost, min_order, max_order, delivery_probability, max_demand );

        while (true) {

            final InventoryState s = new InventoryState(rng, problem);
            final InventorySimulator sim = new InventorySimulator(s);

            final BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            while (!s.isTerminal()) {
                System.out.println(sim.state());

                final String cmd = reader.readLine();
                final String[] tokens = cmd.split(",");

                final InventoryAction a;
                if ("n".equals(tokens[0])) {
                    a = new InventoryNothingAction();
                } else {
                    final int product = Integer.parseInt(tokens[0]);
                    final int quantity = Integer.parseInt(tokens[1]);
                    a = new InventoryOrderAction(product, quantity, s.problem.cost[product]);
                }

                sim.takeAction(new JointAction<InventoryAction>(a));

                System.out.println("r = " + Arrays.toString(sim.reward()));
            }

            //         System.out.print( "Hand: " );
            //         System.out.print( sim.state().player_hand );
            //         System.out.print( " (" );
            //         final ArrayList<int[]> values = sim.state().player_hand.values();
            //         for( int i = 0; i < values.size(); ++i ) {
            //            if( i > 0 ) {
            //               System.out.print( ", " );
            //            }
            //            System.out.print( Arrays.toString( values.get( i ) ) );
            //         }
            //         System.out.println( ")" );
            //
            //         System.out.print( "Reward: " );
            //         System.out.println( Arrays.toString( sim.reward() ) );
            //         System.out.print( "Dealer hand: " );
            //         System.out.print( sim.state().dealerHand().toString() );
            //         System.out.print( " (" );
            //         System.out.print( SpBjHand.handValue( sim.state().dealerHand() )[0] );
            //         System.out.println( ")" );
            //         System.out.println( "----------------------------------------" );
        }
    }

}