09 Nov 2011


Tomas Petricek: F# Math (II.) - Using matrices for graph algorithms

In the previous article of this series, we looked at complex and BigRational, which are two numeric types that are available in F# PowerPack. Aside from these two, the PowerPack library also contains a type matrix representing a two-dimensional matrix of floating-point values.

In this article, you'll learn how to work with matrices in F#, using some of the functions provided by F# PowerPack. I'll demonstrate the library using an example that represents graphs using a, so called, adjacency matrix. If you're not familiar with this concept, you don't need to worry. It is quite simple and it will be clear once we look at an example. The matrix represents which vertices of a graph are connected with other vertices by an edge. Many of the standard operations on matrices are useful when working with adjacency matrix, so this tutorial will cover the following:

This article is a part of a series that covers some F# and F# PowerPack features for numerical computing. Other articles in this series discuss matrices, defining custom numeric types and writing generic code. For links to other parts, see F# Math - Overview of F# PowerPack.

09 Nov 2011 1:46am GMT

08 Nov 2011


Jordi Mas: gbrainy 2.06

Here we have gbrainy 2.06, a minor release that represents 3 weeks of work. gbrainy is a game that challenges your logic, verbal, calculation and memory abilities.

What's new in version 2.06 (since 2.03)


* http://gent.softcatala.org/jmas/gbrainy/gbrainy-2.06.tar.gz
(md5sum 216ce6e151b526075c5938344ed697c5)

Additionally, gbrainy is available for all major Linux distributions.

Windows version

As part of releasing gbrainy 2.06, I created a new Windows version package. You can download it as usual from SourceForge.

On-line version

gbrainy is also available on-line. All games except memory games are available. This is far from ideal in terms of usability but is still a work in progress and I hope to make more progress during the summer.

Help Wanted!

You can contribute to gbrainy in many ways, but actually I'm specially looking forward help on these areas:

Report any issue by fill up a bug in gbrainy bug tracking, sending a message to the gbrainy public group or just dropping me a quick message (jmas at softcatala dot org). Your help is really appreciated.


Finally I want to say thanks a lot to all the people that has participated in this release: translators, people reporting bugs, giving feedback, etc. You contribution has been key as usual!

08 Nov 2011 8:03pm GMT

07 Nov 2011


Joe Audette: IOS 5 Finally Supports WYSIWYG Editors

More and more people are accessing the web using smart phones and tablets and while much progress has been made to provide a good web experience for those devices, until now one major shortcoming has been the lack of support for use of web based WYSIWYG editors like CKeditor and TinyMCE. The problem has been that while the WYSIWYG editors would display ok, they did not trigger the keyboard input so they were not usable because clicking/touching them did not put the focus in the editor and did not bring up the keyboard. The best solution we could come up with was to force the use of a plain old textarea which would trigger the keyboard but required entering raw html making it more tedious to use and requiring knowledge of html from the user. We tried to make it a little better by using MarkitUp to at least provide a toolbar with some helpful html elements as shown below in this screen shot from an old iPhone 3.

iPhone 3 editor

HTML 5 actually defines a contentEditable attribute which is intended for use in making web pages editable but it wasn't supported in previous versions of IOS/Mobile Safari until now with the recent release of IOS 5. Fortunately for us the makers of the popular open source WYSIWYG editors have been working on this using the beta versions of IOS 5 so that now since the official release both of these editors can work in iPhones and iPads that have IOS 5. Shown below is a screen shot of TinyMCE used in iPhone 4S.

TinyMCE in iPhone

We've modified mojoPortal to take advantage of this and not force the plain textarea if we detect an IOS 5 device. This change is already in our source code repository and will be in the next release of mojoPortal. You can also try it out on our demo site using your IOS 5 device. For other devices we still use the textarea approach but I suspect that over time we will be able to enable the WYSIWYG editors for even more devices.

I'm very excited that this major limitation has been overcome in IOS 5 and especially for iPad which is a great web browsing experience and now is even better since you can actually edit your content easily. Huge kudos to the developers of TinyMCE and CKeditor for their great work in supporting mobile devices.

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07 Nov 2011 7:19pm GMT