Dear SasView user, You are receiving this email as a subscriber to the SasView user list and we wanted to let you know that version 4.0 is finally close to being released! While 4.0 has a number of bug fixes and feature requests added, the primary change is a complete rewrite of the way the fitting models are incorporated. The most important change simplifies the interface to SasView so that all built-in models can be used directly as custom plugins. This means, for example, that existing models can be altered for a specific purpose with relative ease. It also means that models that require C for speed are now supported --- in fact without the need for you to install a separate compiler! Just write your properly written and named C code in the plugins directory alongside the python module that calls it. Version 4.0 also makes all the infrastructure for built-in models, such as polydispersity functions, available to custom models. As part of this major refactoring, we also have taken advantage of the fact that all modern computers including laptops have a certain amount of GPU (graphical processor unit) power. As long as you have the OpenCL driver installed SasView will default to utilizing your GPUs when needed. OpenCl comes installed by default with Macs and many - but not all - PCs. Preliminary tests show that model-fitting, say, cylinders can get a 10-fold speedup. Should GPUs not be available on your machine, SasView will still utilize multiple CPUs. Finally, the model documentation has been extensively reviewed, checked, and edited. With such a massive restructuring there were bound to be “unexpected consequences” that came to light… and they did! The development team now believes that except for the tickets currently listed under Milestone 4.0.0 at http://trac.sasview.org/report/3 the beta 1 pre-release is robust enough for use in real applications. We are planning to have the full release available by the end of September. In the meantime, we would very much appreciate any feedback from your experience, and particularly bugs you find we may have missed. Thanks and we hope you enjoy the new version. The SasView Development Team