News

New Music Page with Free Chaos in the Realm

A new page has been added to the site, covering music that I like, as well as music I have written and played myself through the years. It kicks off with a free EP from the band Chaos in the Realm, which haunted the rock taverns of Melbourne back in the mid-90s.

Forpedo: a preprocessor for generics in Fortran

I have just released Forpedo, a preprocessor written in Python that allows you to use generics (like templates in C++) in Fortran code. It is easy to use, and example code is provided. Download it directly by clicking here, or see the Forpedo web site.

ADF Without the Command Line

ADF2004 includes a more Mac-like interface for the GUI modules. The X11 modules have been bundled into a native Cocoa application, so that they can be started from the Finder, or dragged-and-dropped onto the Application icon. With these changes, it is possible to use ADF without the command line at all, and it integrates much better with other aspects of Mac OS X. ADF2004 for Mac OS X is available now from SCM.

New Article on Xgrid and Cocoa

MacDevCenter has just published a two part article I wrote about integrating Xgrid into Cocoa apps on Mac OS X. You can find part 1 here, and part 2 here.

Xgrid is new grid technology from Apple. Like most things that come out of Apple, Xgrid takes an existing concept, and brings it within reach of ordinary computer users. In the article, I postulate that we are seeing the beginning of the Democratization of Distributed Computing.

In part 1, Xgrid is introduced, and I demonstrate how you can use it from the command-line to create a simple distributed compilation system, like distcc in Xcode. In part 2, I move on to creating a batch image processing app with Cocoa. Source code for all examples is available for download.

Gradient Smoothing in ADF

The recently-released ADF2004 includes new gradient smoothing technology that I have developed over the past year. Geometry optimizations and frequency calculations should benefit from this new functionality.

ADF’s integration point generation is best-in-class, but it has a nasty side-effect: small perturbations in geometry can cause the energy gradient to ‘jump’, rather than vary smoothly. This comes about because ADF generates integration points using the Voronoi cells of the atomic centers, and the topology of the cells is not stable for changes in geometry. This can lead to problems when the gradients are used to generate the hessian (second derivative matrix), such as in geometry optimizations and frequency calculations.

The new smoothing method works by reusing the cell topology from one geometry to the next. As long as the geometry does not vary too greatly, the cells can be frozen, and the integration points smoothly perturbed, leading to smoother variations in the gradients.

On the Periphery of Reaction Dynamics

Work has begun on a new quantum scattering package for surface reactions, called Periphery. Written in C++, Periphery will be based on solid software development practices, contrary to the vast majority of scientific programs.

Initially, Periphery will incorporate time-independent coupled-channel methods, but future extensions should include time-dependent wavepacket methods.