This course uses the CodePost web site for assignment submission and grading. Students submit homework assignments to CodePost and graders annotate student submissions and assign grades there. Most of the time the system works quite well, but sometimes it doesn’t. Before sending an email to your TA or your instructor, please read this page.

1. Don’t email your sets to us

One way or another, your sets are going to have to go onto CodePost in order for a grade to be assigned. Emailing your sets to us "as proof that you completed the assignment" is not helpful; we trust you, but we need to work through the problem, and bypassing CodePost is not an option.

2. Things to try when you can’t submit your set

There are a number of things that can go wrong when you try to submit your set. The most common is a message to the effect that "this submission is under review and can’t be resubmitted". If that is true (you actually did submit your set already) you may just have to wait for your grader to grade your set. Be aware that CodePost can sometimes succeed in uploading your set even when it seems like it fails, so if you try again it won’t let you upload it a second time.

Here are some steps you can take if you can’t submit your set:

a. Wait an hour and try again

This may sound silly, but it works quite often.

b. Log out of your computer and back in again, and try again.

If your browser or computer is in a weird state, things can malfunction, so it’s never a bad idea to restart both of them.

c. Try a different web browser

We recommend you use either Google Chrome or Firefox as your web browser to submit your homework. If you use something else (e.g. Safari or Microsoft Edge) we can’t guarantee that CodePost will work properly. This is by no means CodePost-specific; lots of web sites "only work on Chrome", for instance. Installing Chrome or Firefox only takes a few seconds and then you are (probably) good to go.

d. Try a different computer

You might be running a computer with a very old operating system, or (conversely) a very new one. Either of these could affect the way your browser works, so before coming to us you should try to submit your set on a different computer if at all possible.

e. Try a different internet connection

Bad internet connections can sometimes prevent CodePost from working. If your wifi doesn’t work, or doesn’t work reliably, try a different wifi connection (even if you have to physically move your computer to do it).

3. If all else fails

If you’ve tried everything we mentioned above, and you still can’t submit your set, you should contact Mike at mvanier@cms.caltech.edu. He may want to set up a video meeting to make sure that you are using the site correctly and to see exactly what happens when you try to submit your set.