PSYC161 Homework #1

This homework is a part of the PSYC161 Introduction to Programming for Psychologists & Neuroscientists course work.

Ultimate goal

On the example of a simple Python script/function establish practice of

• interaction with Git and GitHub
• automated testing using py.test
• code syntax conventions validation using flake8

Problem to solve

We are creating a new design for an fMRI experiment, for which we will have a single trial per each of n different independent conditions per run.

Question: how many possible trial orders there could possibly be?

Approach: estimate the factorial of n

Solution:

1. Write factorial to estimate factorial of an integer n (could be plain iteration or a recursive call). See wikipedia if not sure about what factorial is

"Extra credit"

2. Write both recursive and non-recursive version of a factorial function

3. Investigate difference (well - ratio) in time of execution between the two. Use time module to track time.

HOWTO

• "Fork" (which is really just a GitHub term for "clone" on GitHub site, no "git clone" to be done to local drive), this repository on GitHub

• In the terminal now run

    git clone https://github.com/YOURLOGIN/psyc161-hw-factorial
  

  to "clone" your remote fork/clone to your local drive

• Edit file factorial.py which provides a skeleton for your work

• You are welcome to use any editor to edit the file, but we recommend starting to work with PyCharm

• Function factorial definition provides a skeleton for you to fill in (docstring + implementation)

• Test test_factorial() implements basic checks already which you need to expand to degree you feel necessary to state with assurance that your implementation. You can run all tests_ present in the file using python -m pytest -s -v factorial.py (run man pytest in a terminal to check what options -s and -v are for. Do you need them both really ATM?)

• git commit -m "Description of your changes" -a your work. Could be done multiple times

• Make sure that your code passes tests, and also conforms to PEP8 - Style Guide for Python Code by running flake8 factorial.py and addressing noted issues.

• Whenever you are ready to submit your homework, run git push to push your changes back to your clone on GitHub

• Visit your GitHub page (http://github.com/YOURLOGIN/psyc161-hw-factorial) and find your changes being present among Commits, and "Send a pull request" option present.

• Send a "Pull request" against my original repository for review of the changes etc.

• Review status of the pull request in a few minutes -- it should report successful pass through travis CI run which runs again pytest and flake8 on my behalf. If not -- inspect travis's logs, commit fixes locally, push them to github again so that PR gets updated, and travis gets another run.