KDE for scientific work

Advanced calculator runner

Hello Planet!

since this is my first post on the Planet, I’ll shortly introduce myself and my activities in KDE. My name is Matteo and I am the maintainer of the Qalculate plasmoid and runner since SC 4.5. I am also the founder and maintainer of Cirkuit, a KDE app to produce publication-ready graphics using different backends (TikZ, Circuit Macros, Gnuplot).

In this post, I would like to describe some features that have been introduced in SC 4.5 (and polished for SC 4.6) in the Calculator runner. The reason for this post is that apparently many people are not familiar with many of the features offered by the Calculator runner since 4.5.

First of all, how do you use the runner? Simply press ALT+F2 and type a mathematical expression with a ‘=’ sign at the beginning or at the end of the statement, as shown in the figure below.

Since KDE SC 4.5, the calculator runner has an optional (compile-time) dependency on libqalculate. So, if you compiled kdebase with libqalculate support enabled, the runner has some “advanced” features, like unit conversion, exchange rates, equation solving, and many more.

This means that you can perform calculations involving Newton’s laws of motion or Ohm’s law just by pressing ALT+F2 and typing the expression (see pictures below).

You can’t remember the derivative or integral of a certain function? This can also be accomplished by the runner:

You can also solve equations:

You can find out additional features at the Qalculate website. I will write an additional post about the Qalculate plasmoid, illustrating more features of the Qalculate engine. Feel free to suggest improvements in the comments.

25 responses to “Advanced calculator runner

  1. slack December 7, 2010 at 6:25 pm

    ohhh nice :D, i started to use a lot of symbollic math program ’cause i am in the first year of engineering, with this i don’t need to open maxima for a single derivate or integrate.

    thank you 😀

  2. Thijs December 7, 2010 at 6:27 pm

    Wow…. how I never new about these feature, while using the krunner all of the time. Cool beyond measure!

  3. Samat Jain December 7, 2010 at 7:37 pm

    Great to see qalculate’s features becoming accessible through KRunner!

    A tangential aside: are there any plans to port the conventional qalculate KDE application to KDE4? I still like it and use it over the qalculate plasmoid—it keeps history, and the menus make it easy to find the names of functions.

    • sciencekde December 8, 2010 at 12:06 pm

      Well, since the infrastructure (i.e. the Qt4 interface) is ready, it wouldn’t be too difficult to port the main app to KDE4. The main limitation from my side is time. If someone is willing to volunteer for the task, I would be extremely happy to help.

  4. damipereira December 7, 2010 at 7:47 pm

    Great! I’ve always loved qalculate and also the plasmoid, I didn’t have an idea it was integrated into krunner.
    now the only thing it may need is history, for some reason the calcs doesn’t appear in history, if it could have this or memory it would be awesome

  5. burkeone December 7, 2010 at 7:58 pm

    Thats nice. but you forgot to include one of the easiest things to your fancy runner; the comma. You always have to write 2.5 instead of 2,5. Thats a pitty.

  6. arieder December 7, 2010 at 8:04 pm

    Cool stuff.
    Any chance you are interested in reviving the Qalculate Cantor backend, that is lying around in playground?

  7. Stu Jarvis December 7, 2010 at 9:50 pm

    Impressive 🙂 I’m also loving the idea of the blog.

    It would be great to see you in the kde-science mailing list ( which is quiet and could do with some energy.

  8. crabman December 7, 2010 at 10:03 pm

    I use kde for my scientific work everyday – and had no idea how powerful the qualculate krunner was. Please add it to the documentation somewhere! I bet none of my collegues knows this as well.
    And writing gnuplot scripts with highlighting and live preview is an amazing idea.

    I wish you had made this blogpost six months earlier – and there were packages for opensuse 11.2.

    • sciencekde December 8, 2010 at 12:08 pm

      Thanks for the comment. I know I should’ve blogged about this earlier… my fault. I will blog about my other project Cirkuit (and the gnuplot live preview) in the (near) future.

  9. Pingback: Tweets that mention Advanced calculator runner « sciencekde --

  10. Shafqat Bhuiyan December 8, 2010 at 7:14 am

    Wow it’s been 4 months since KDE 4.5 and I didn’t even know this existed!

    I hope more developers talk about the features they implement (even the little ones) because they are often hard to spot.

  11. Jeffery MacEachern December 8, 2010 at 10:09 am

    Excellent! As an engineering student, this should be very useful.

  12. bay December 8, 2010 at 8:47 pm

    Cool! But why is it necessary to enter the ‘=’ sign in the begining? Is it restriction of krunner plugins API or something else?

  13. Lundgaard December 17, 2010 at 10:19 am

    This is some truly great features… Have been using some of them, but didn’t know about the solve and diff, etc stuff. Just great, keep up the good work.
    There is one thing though: i would like to have the stuff i entered as calculations to appear in the krunner history (ie. when i use the up arrow to find previous commands). This would really be a nice addition, since you (at least I) often mistype a single number or just forgot some part of the calculation and don’t realize until after closing the krunner drop-down.

  14. Pingback: Realiza operaciones matemáticas avanzadas con KRunner : KDE Blog

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