ScienceKDE
KDE for scientific work
Advanced calculator runner
December 7, 2010
Posted by on 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.
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 😀
Wow…. how I never new about these feature, while using the krunner all of the time. Cool beyond measure!
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.
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.
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
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.
I’ve just committed a fix for this yesterday (and it will be included in SC 4.6), so the decimal point symbol is now localized correctly.
Cool stuff.
Any chance you are interested in reviving the Qalculate Cantor backend, that is lying around in playground?
Yeah, it is on my todo list. I’ll try to work on it when I have some free time.
awesome!
Impressive 🙂 I’m also loving the idea of the blog.
It would be great to see you in the kde-science mailing list (https://mail.kde.org/mailman/listinfo/kde-science) which is quiet and could do with some energy.
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.
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.
¡Excellent! =)
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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.
Excellent! As an engineering student, this should be very useful.
Cool! But why is it necessary to enter the ‘=’ sign in the begining? Is it restriction of krunner plugins API or something else?
Actually it was already present in the “old” calculator runner and I didn’t want to change its behavior. I guess it’s an easy way to tell the parser to interpret the statement as a calculation and not to pass it to other plugins…
FIY, you can enter it after the expression as well, ie: 2+2=
thank you. I really missed that feature.
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.
Yes, history would be a nice addition (it is already present in the plasmoid btw). Expect it in the next release.
Thats just great to hear 🙂
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