Christian Lawson-Perfect

A new part type: matrix entry

We’ve got a pretty big new feature for Numbas this week – a whole new part type! The matrix entry part asks the student to enter a matrix.

In the past, we’ve hacked together questions where we ask the student to enter a matrix by putting a load of gapfills in a table. That was very laborious to set up, and the user experience for the student wasn’t particularly great.

The matrix entry part is meant to make all this a lot smoother – you give a JME matrix variable as the correct answer, and the student is shown a (optionally resizable) grid of cells to enter their answer.

It works like this:

numbas matrix part

The student picks the size of their answer, then enters numbers in each of the cells. It’s marked as correct if the matrix they give exactly matches the one you give.

If you want, you can lock the size of the answer matrix, so the student doesn’t have to be shown the size picker interface. That looks like this:numbas matrix entry no size

There are a few other options:

  • You can award the marks proportionate to the number of correct cells, instead of a simple pass/fail.
  • You can mark cells as correct if they’re within a given margin of error of the correct answer.
  • The precision restriction options from the number entry part are also available here.
  • You can allow the student to enter their answers as fractions (this is also available for number entry parts now)

You can see all that in action in this demo exam I created, containing a few simple-ish matrix entry questions. And of course, there’s documentation.

New tools to test generated variables

One thing that many people have asked for over the years is the ability to check whether the variables generated by a question have a desired property, and “re-roll” them if not. I’ve been reluctant to implement this because it can lead to sloppy question design when a method that’s guaranteed to work can often be found with a little bit of thinking.

Read the rest

Development log – November 2014: version tracking!

Here’s another round-up of recent development work on Numbas.

Version tracking

The big new feature is version tracking – every change made to a Numbas question or exam is saved in the database, and you can revert to old versions in the new “Editing history” tab. Read the rest

Development log – September 2014

Here’s another round-up of the development work on Numbas in the past month-and-a-bit.

A little attribution

I’ve added a small attribution footer to the bottom of the default theme. It looks like this:

created using numbas

Now that people can upload their own themes, we wanted an unobtrusive way of noting that tests are built using Numbas. If you don’t want it there, you can use a modified theme to remove it, but we’d prefer you kept it. Read the rest

Responsive layout on mobile devices

On small screens (tablets and phones, mainly), the default Numbas theme didn’t used to leave much space for the question content.

I’ve spent the past couple of days making the theme responsive, so screens less than 980px wide switch to a more vertical layout. The question menu and pause/end buttons move beneath the content area, and the banner is more vertical too. This means the content area can have the full width of the page. Read the rest

Upload your own extensions to the Numbas editor

A couple of weeks ago I made it possible to upload your own themes to the editor, so it makes sense to also allow you to upload your own extensions.

Extensions in Numbas can affect any part of the Numbas runtime. Typically, that means adding new functions in JME or javascript (or even a new JME data type) to avoid repeating the same code across several questions.

I’ve written some instructions on how to write an extension, along with a couple of examples, in the Numbas documentation.

Upload your own themes to the Numbas editor

Numbas has always had support for themes, allowing you to completely change how exams are displayed. The Numbas editor, however, only supported a static list of themes installed by the server administrator, so most users were stuck with the default themes.

I’ve just released an update to the Numbas editor which allows any user to upload a .zip package of their own theme, which they can then use in any exam. You could use this to do something simple such as show your institution’s logo instead of the Numbas one, or add some CSS rules to tweak the layout of the page.

I’ve written some brief instructions on how to create your own themes, along with a couple of simple examples, in the Numbas documentation.

Development log – July 2014

Development on Numbas continues apace, so I thought it’d be a good idea to start writing about changes in more detail here so they don’t slip by unnoticed. Read the rest

New search interface, talks, and a mailing list

Last week I deployed the new question search and organisation interface to the mathcentre editor. We noticed that the global question database was becoming quite unwieldy now that we have so many users (not complaining!), and finding both your questions and good questions written by others was getting harder. The new interface downplays the big list, instead presenting you with a few different ways in to the most useful parts of the site.

numbas new question index

The questions index page now shows you a kind of ‘dashboard’, with links to the most popular tags, your recently-edited questions, as well as some highlights picked by us and your starred questions – you can save a question to this list by clicking on the star next to its name on the question edit page. You can still search the entire database by entering keywords or question titles in the search box at the top of the page.

It’s not a coincidence that we also delivered a workshop on using Numbas at eAssessment Scotland 2013. An hour really wasn’t long enough to do very much at all, but everyone seemed very positive about Numbas and keen to investigate it further. I asked for a show of hands at the start to find out who had signed up for the workshop because they’d already heard of Numbas, and I was pleasantly surprised by the response!

In future conference action, James Denholm-Price of Kingston University London will be giving a talk titled “Using Numbas for formative and summative assessment” at CETL-MSOR 2013 on the 10th of September. James used Numbas in his linear algebra course last year and has many interesting things to say about it. Also at CETL our two summer students, Hayley Bishop and Sarah Jowett, will be talking about their work on the maths support wiki we’re creating with Birmingham University, to complement our respective maths support centres. More on that later!

On the 23rd of October I’ll be giving a talk about Numbas at an IOP-sponsored event on “Promoting learning through technology” at Edinburgh University. I don’t think the event has a webpage or even a definite venue yet; I’ll give details when I have them.

Finally, we’ve set up a numbas-users mailing list on Google Groups. The idea is to have a place to discuss Numbas use, ask and answer questions about authoring, and talk about features you’d like to see. Bill has started it off by asking for comments on the new searching interface.