Sunday, 29 August 2010


The F#.NET Journal just published an article about typeful programming:

"The pedagogical calculator sample demonstrates how a program can evaluate mathematical expressions originating from the user interface of a calculator. This article describes the design and implementation of a calculator application that uses Windows Presentation Foundation to provide a graphical user interface similar to that of a traditional calculator. In particular, every effort is made to leverage static checking in order to catch as many bugs at compile time as possible. This includes not only sophisticated union types to represent the state of the state machine but also exhaustiveness and redundancy checking of the advanced pattern matches that result as well as their factoring to reduce code size..."

To read this article and more, subscribe to The F#.NET Journal today!

Wednesday, 18 August 2010

Don Syme lecturing at the F#unctional Londoners Meetup

Creator of the F# programming language and all-around great guy Don Syme will be giving a lecture at the F#unctional Londoners Meetup, Skills Matter eXchange, on 9th September 2010.

Saturday, 7 August 2010

Jon Harrop lectures on Parallel QR Decomposition

The Skills Matter eXchange have kindly uploaded the video of my recent lecture as well as the accompanying slides.

The core of this lecture is an explanation of why purely functional code that looks embarrassingly parallel often does not scale and how scalability can be achieved through the use of mutation.

The example used is QR decomposition where pure code achieves less than 2× speedup on 8 cores but impure F# code achieves over 7× speedup and beats the reference implementation of BLAS and LAPACK with 99% less code. However, the lessons learned are not specific to this algorithm or even to numerical methods in general but apply to all software running on .NET.

For vastly more information on this subject, stay tuned for our forthcoming Multicore .NET book.

Wednesday, 4 August 2010

Data structures: heaps

The F#.NET Journal just published an article about data structures:

"A min-heap is a tree-based data structure that satisfies the constraint that the children at any given branch are always larger than their parent and, consequently, the minimum element is at the root. Heaps are most notable as an efficient way to implement priority queues which, in turn, underpin a variety of algorithms including some seen in previous F#.NET Journal articles. This article examines skew heaps, leftist heaps, pairing heaps and splay heaps..."

To read this article and more, subscribe to The F#.NET Journal today!