Assignment 4

1. (30 points) Make a copy of the Pathfinder project from Chapter 5.
In the copy, find where Heuristic_Euclid is defined (look in the
common folder), and change the method so that it approximates the
Euclid distance with a linear approximation.  Remember from class that
if (x,y) is a 2D vector, a linear approximation to it's length is
given by the formula

        let u = max(abs(x), abs(y))
        let v = min(abs(x), abs(y))
        distance = u + 0.336358*v
or
        distance = 0.960434*u + 0.397825*v

The first approximation formula has a maximum error of 5.5%, and the
second approximation formula has a maximum error of 4.0%.  You only
have to use one of the approximation formulas, and it is your choice
as to which one you use.

Run the modified copy using the A* algorithm with the source and
target far apart from each other and in different columns and rows
from each other so that lots of red lines appear (paths that are
explored but not part of the final solution).  Note the time it took
to find the lowest-cost path (shown at the bottom of the window).
Run the original pathfinder project with the source and target in the
same place as they were when you ran the modified copy.  Email to the
TA a screen capture of the run of the modified copy, and the times
taken by the two runs.  We are trying to see how much faster the
linear approximation is to the original Euclid formula.

2. (60 points)  The ScriptedStateMAchine project from Chapter 6
implements a simplified version of WestWorld1 project from Chapter 2.
Right now minor Bob has three states he can be in: GoHome, Sleep, and
GoToMine.  Make a copy of the ScriptedStateMachine project and modify
it by adding two new states in the Lua script: QuenchThirst and
VisitBank.  These should be comparable to the QuenchThirst and
VisitBankAndDepositGold states in the WestWorkd1 project, only now
they are written in the Lua script file.  You will also have to make
some minor changes to the java files as well (at least in Main.java
and Miner.java). Run the modified copy project, get a screen capture
showing a part of the generated dialog in which is shown the
statements produced by both of the new states at least once. Send to
the TA a document showing that screen capture and the segments of code
you added to the project. (You don't have to include whole files, only
the parts of the files you added or changed.)