BWSI CogWorks Online Course: Graded Assignments

Version: 1.0.0

Please consult the BWSI CogWorks course page for the due dates for the respective problems.

Installing the auto-grader

Complete Module 1 of PLYI to install and configure Python on your computer, via Anaconda.

In order to run the auto-grader for these problems, you must install bwsi_grader. In your terminal, execute:

pip install bwsi_grader

This grader requires you to use Python 3.7 or later.

Completing an Assignment

1. Open the Jupyter notebook for the problem of interest

The coding problems are provided in Jupyter notebooks. Refer to this section of PLYMI for instructions for starting a Jupyter server, and for opening a Jupyter notebook.

Make sure that the conda environment from which you start the Jupyter server is also the one that you installed bwsi-grader in.

2. Read the problem description

Throughout notebook will be a detailed descriptions of each part of the proble, problem. You will also often be provided with example that demonstrate how your function ought to behave. Read through this material carefully.

Feel free to post questions on the course's piazza page.

3. Begin working on a solution

For each problem, you will be provided with the template for a function that you are to complete in order to solve the problem.

Whenever you make changes to that function, you must execute the notebook cell containing the function's definition in order for those changes to take effect.

4. Test your function

Before you run the auto-grader, you should test your solution with some examples. You will save a lot of time if you build an intuition for the solution that you are working on, and see if it behaves as you expect, before submitting your solution to the auto-grader.

Note that every problem gives you example use-cases for your function, complete with the input to the function and the expected output. These are ready-made test cases for you to use. Make a new cell in your Jupyter notebook and try running your function yourself; do you see the output that you expect?

Some Common Issues

"My function doesn't return anything when I run it!"

• Did you include a return statement in your function? If not, your function is returning None
• Is there an asterisk to the left of the cell where you are running your function? If so this means that your code is still running. Almost all of the solutions to these problems should run quickly (within a few seconds); if your code is running for a long time, there may be a while-loop in your code that is running forever. If this is the case, kill your notebook's kernel and inspect your function for while-loops that fail to end.

5. Submit your solution to the auto-grader

The notebook will contain a cell that imports a function from bwsi_grader and passes your solution to this. Running this cell will run your solution through the grader.

You can run the grader as many times as you like.

If there is a problem with your solution, the grader will try to print out a descriptive error message for what went wrong. It will also show you how your function was called by the grader, and what its expected behavior was; read this message carefully to understand how to fix your code.

If your solution is correct, the grader will print out a message saying so, and will print a hash code that you can submit on the BWSI Python course page, to prove that you completed the assignment.

Some Common Issues

"When I run the auto-grader cell I get an ImportError indicating that the module bwsi_grader cannot be found.

• Make sure that you installed bwsi_grader in the same conda environment from which you are running your Jupyter notebook.

"My function prints the correct solution when I run it, but the grader says that it returns None"

• Did you use a print statement in your code to print the answer, instead of a return statement to actually return the answer? This is likely the cause of this error.