Hi Folks, Version 0.9.31 of Larch has been released. It can be installed using Anaconda Python 2.7 (the recommended approach on Windows and Mac OSX, and a fine choice on Linux too) with conda upgrade xraylarch The source kit can be downloaded from PyPI ( https://pypi.python.org/pypi/xraylarch/0.9.31) or installed on systems that already have Python installed with pip install --upgrade xraylarch Larch is in active development (at https://github.com/xraypy/xraylarch) and this release includes several important new features and capabilities. Some of these are still "in progress" and could greatly benefit from community inputs and comments at every level. In no particular order, some of the highlights include:

Larch server (bin/larch_server) is now much improved and more ready for Athena/Artemis to use. There are still some issues getting Larch Server + Athena working on Mac OSX, but Windows and Linux seem to be working. Using Athena/Artemis with Larch should still be considered experimental, but we're hoping that Larch will soon be the normal backend for Athena and Artemis.

Autobk background removal now calculates arrays for the uncertainty in chi (delta_chi) and mu_0 (delta_bkg) at each k or energy point. These are derived from the uncertainties in the fitted spline coefficients. It has long been argued that uncertainties from the background removal should dominate the uncertainties in chi(k), and so should be used included as the uncertainty in the fits to EXAFS data. Indeed, preliminary tests show that using these uncertainties in the fits does bring reduced chi-square much closer to 1.

Much better support for Python3. Larch is still only supported for Python2.7, mainly due to the dependency on wxPython which is not yet officially supported for Python3. Still, most parts of Larch are Python3 compatible, including the GUIs. If Python3 is a priority for you, let us know (here or on Github), and we'll try to make that happen sooner rather than later.

Support for dealing some X-ray Diffraction data has been added especially for the X-ray Fluorescence maps supported in the Larch XRF MapViewer. New GUI apps for viewing and working with 2D and 1D diffraction images are included in this release. These are the work of Margaret Koker, and are the beginning of support for XRD visualization and analysis in Larch.

XYFit, a GUI for XANES peak fitting has been begun, and can be used for simple sum-of-line-shapes. The abilities of XYFit are currently similar to Athena's peak fitting panel. There are missing important features, but development of this is very active with many features expected to be added over the next few months.

The new GUI components should definitely be considered as experimental and ready for friendly comments, suggestions, and bug reports. These are not quite ready for production use yet, but we're hoping that you can help with feedback and suggestions. So, please consider giving these tools a try, and let us know what you think. --Matt Newville