The directory $UWHPSC/labs/lab20 contains a Fortran code fourier_sum.f90 that computes terms in the Fourier sine series for the function \(f(x) = e^x\) and prints them out to the file frames.txt along with partial sums of the series. It also creates a second file xf.txt that contains the values of x and f(x) on the finite grid where the terms and sum are computed.

The Python script animate.py reads in these two files and produces an animation, which can be viewed at http://faculty.washington.edu/rjl/FourierSum.html.

We will go through these codes.

You may have to install JSAnimation on your SMC project, see

*Animation in Python*.

The subdirectory $UWHPSC/labs/lab20/gamblers_ruin contains a modified version of the solution to Homework 4, part 2, and does a single random walk. The gamblers.f90 code has been modified to print n1, n2 each step to the file walk.txt.

Produce a script animate.py and modify Makefile1 so that you can do:

$ make movie -f Makefile1 n1=10 n2=10 seed=1234

and generate a movie like the one shown at http://faculty.washington.edu/rjl/RandomWalk.html.

Don’t worry about the Makefile at first, get animate.py working.

For testing, you might want to use smaller n1 and n2 so there are fewer png files to generate.

**There is quiz for Lab 20**