Signing up

Follow these steps to setup an account on Autolab (unless you already have one in which case you'll use your existing account):

1. Go to this page and click on the Sign in with MyUB link . A new account will automatically be created for you.
2. I believe Autolab should now be using your preferred name instead of your official UB first and last name. If this is not the case, please let us know ASAP.
3. We will have leader boards for all the programming assignments. For anonymity, all students are identified by their chosen nicknames. So please make sure you pick an appropriate one (you can change your nickname at any point in time).
4. After you have done the above steps, you wait.

What happens next

Here are the steps that we need to take on our end:

1. We will upload a list of UB emails of students registered in the course (students cannot register themselves in a course). After that, you can just login into Autolab using MyUB and you should see the CSE 331 course.
2. If you successfully completed your syllabus quiz, you will be added to the Y section. Otherwise you will be added to the N section.
3. Once you have successfully completed your syllabus quiz, you should be moved to the Y section: if this does not happen within one week of you completing the syllabus quiz, you should send us a reminder.
4. We will only release the grades for section Y.

In the steady state

Here are the various things to keep in mind once you are successfully added to the course on Autolab:

1. Once you log in to the system (after creating your account), you will see all the courses for which you have been registered. CSE 331 should appear with the description CSE331: Algorithms and Complexity (f22).
2. Once you go to the course web page for CSE 331, you will see a list of pending homeworks. To begin with, you should see one box for Quiz and one link for Syllabus Quiz. As you move along in the semester, you will also see completed assignments/homeworks.
3. There will be five submissions/questions for each homework.
4. The interface is reasonably intuitive but make sure to explore and get yourself comfortable with the interface - you will be spending quality time with it this semester!
5. For the autograded questions, you will need to click on any one of your scores to see the feedback.

Autolab Walkthrough

Version of programming languages on Autolab

Java

openjdk version "10.0.2" 2018-07-17

OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.1)

OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.1, mixed mode)

            

Python

Python 3.6.5

C++

g++ (Ubuntu 7.3.0-16ubuntu3) 7.3.0

If you plan to use C++

Our recommendation

We recommend three ways to go about coding in C++ for CSE 331, sorted in what we recommend most to least (though the second and the third options should work OK):

1. This option is the best one since the Virtual Machine (VM) image matches the system being run on Autolab:

   Use the VM image used in CSE 220

   We recommend that you use the VM image used in CSE 220 that is maintained by Ethan Blanton .

   If you have questions on Ethan's setup, please do NOT contact him: email cse-331-staff@buffalo.edu instead.

   If you still prefer to use your own system, we would recommend that you still test your code in the VM system above before submitting to Autolab.

   The only potential drawback is that virtual machines might not work well on the latest Apple machines. If this is true for you, please use the next option.

   Using VM image on Windows

   If plan to run the VM on Windows then Fall 2022 onwards, we recommend that you rub it using Virtual Box (and not VMWare). Here is a walkthrough video by Nick Minor on installing the VM on Windows using VirtualBox:

   Using VM image on MacOS

   Unfortunately, it looks like VirtualBox does not work that well on MacOS. We're looking into fixes.

   In the meantime, using VMWare on MacOS might be the only option. If you already have a VMWare license that lasts until the semester ends, then you should be all set. If you need a license please email Atri ASAP.

   Some comments on the VMWare option

   The comments below are based on testing in Fall 21 on a Mac machine (Big Sur OS), though most of the comments below should be OK for installation on a Windows machine as well:

   • The ova that you need to download is big and depending on your Internet speed might take time. Also the initial setup of the VM takes time -- this is because you are basically setting up a new Linux machine on your machine! Be prepared for the overall process to take a couple of hours. (It's mostly idle time waiting for things to happen, so you can safely multiplex the deployment with other work.)

   • Do not try to share folders

     If possible, use the VM as if it were an independent machine: i.e. download the coding templates using the browser in the virtual machine, create and test your code in the VM and then submit to Autolab using the browser in the VM.

     If for some reason you really want to share folders/files between your machine and your VM, it might mean extra work. Here are some starting points (again based on testing on mac):

     1. You need to enable sharing folders:
        • For Windows machines, use these instructions .
        • For MacOS machines, use these instructions .
     2. At least in our testing on Mac, the shared folder did not show up in /mnt/hgfs. To fix this, use these instructions .

2. In case the above VM option does not work for you, then we recommend that you use a departmental server by sshing into it:

   Use a departmental server

   Login to one of the departmental servers accessible by students and then run your code in there. Pick one of the servers that are described as General compute server for short, interactive timeshare jobs. timberlake.cse.buffalo.edu is one commonly used by students.

   Unlike the VM options, you will need Internet to access the servers. Also unlike our first recommended option, the environment on departmental servers will not match the one on Autolab exactly but we do not expect this is to an issue.

   If you still prefer to use your own system, we would recommend that you still test your code on a departmental server above before submitting to Autolab.

3. Until Fall 19, this was our main recommended option but this has not been updated for a while. We think it should be OK to use this option but your mileage might vary.

   Use a VM with g++ installed for Ubuntu

   You should install a VM that runs g++ on Ubuntu. In particular, we recommend that you use Jaric Zola's VM system that he created for his CSE 250 course . If you have questions on Jaric's setup, please do NOT contact him: email cse-331-staff@buffalo.edu instead.

   If you still prefer to use your own system, we would recommend that you still test your code in the VM system above before submitting to Autolab.

   Some comments on the instructions in Jaric's setup

   Below are some comments that are hopefully helpful:

   • He is not kidding about the time it takes for the initial deployment. Make sure you have a good hour or two dedicated for this. (It's mostly idle time waiting for things to happen, so you can safely multiplex the deployment with other work.)
   • A clarification about the files in the /vagrant directory: in the VM, the /vagrant directory will have exactly the same contents as the directory where you clone the git repo.

Running HW C++ template code on Linux

If you plan to use Java

Click here for the Instructions

Dealing with Errors

• Unexpected token error: This usually happens when your code exceeds the global 180 second time limit for all testcases. Look for Autodriver: Job timed out after 180 seconds in the feedback. If you don't see this as part of the feedback please contact the course staff.
• UnicodeDecodeError: This is most likely because you have one or more non-ASCII characters in your code. First double check that you submitted a source file and not a binary. If the error persists, run this Python script on your Solution file by executing python3 validate_ascii.py <filename>. This will print the line numbers with non-ASCII characters in your code, which you should then remove.
  • If the above does not work check to make sure that the text that you are entering in the textfields Sources and MaxInputs during submission do not have any non-ASCII characters either (since that also results in a similar UnicodeDecodeError).

Description of Thresholds

Your solution times out if it crosses a certain threshold, as noted in the Autolab feedback. The way it works is as follows: we run our code and multiply our time with the corresponding threshold factor for the input to get the final threshold. Thus, your solution will be within the threshold if it is slower relative to the optimal solution by at most the corresponding factor. For example, a threshold factor of 40 for input 1 means your code can be at most 40 times slower than our optimal solution. These threshold factors tend to be used for pretty much all the programming questions, although sometimes we end up changing them depending on the problem etc.

Frequently Asked Questions

• How often can I submit my answer for any question on Autolab? + -
  You can submit as many times as you want before the deadline. Autolab will take your latest score for Q3, and we'll grade your latest submission for Q1 and Q2.
• How can I look at the feedback I receive on Autolab? + -
  For question 3, you can click on any of the scores for a submission (usually available within a few minutes). For questions 1 and 2, the grades and feedback will be released manually and you'll be notified through a Piazza post. Once the grades are released, you'll be able to open your submitted file and look at the grader's feedback.
• Why can't I see my printouts in the Autolab feedback? + -
  Print statements are disabled on Autolab for security reasons. However, you can run and print your code locally before submitting to Autolab.
• How can I tell if my code is timing out on Autolab? + -
  Autolab feedback will let you know if your code exceeds a threshold time for a testcase. However, if your code exceeds the global 180 second time limit (for all testcases), then the feedback may be cut off. In that case, it is recommended that you submit your code to run on fewer testcases to figure out the bottleneck.
• What do the textfields MaxInputs, Sources, and Collaborators mean? + -
  MaxInputs is only relevant to the third (programming) question, where you can specify the number of testcases you want the Grader to test your code on (for partial credit). This is especially useful if your code times out if you run it on all 10 inputs. Sources and Collaborators applies to all assignments and their use is outlined on the Homework Policy page.

Java Specific

• How do I import my project to Eclipse? + -
  Select File > Open Projects from File System... then select the directory you wish to open.
• How do I run my project with arguments in Eclipse? + -
  Right click the Class you wish to run (in 331's case it will be Driver) and select Run As > Run Configurations and the Run Configurations window will open. Make sure that in the left column of the window the desired class is selected under Java Applications. Select the Arguments tab, then write any arguments in the Program Arguments box you would like to include, then click Apply (arguments should be separated by spaces).