[Ifeffit] Larch 0.9.38

Matt Newville newville at cars.uchicago.edu
Sat Jul 7 23:04:31 CDT 2018

Hi Folks,

Version 0.9.38 of Larch has been released and binary installers are now
available for Windows, MacOS, and Linux.  There have been many minor
improvements made in the past several months, particularly for the XAS
Viewer application. XAS Viewer is now very close to having feature parity
with Athena and Sixpack, with a few things still missing and a few things
slightly improved.  This should be of particular interest for Mac users,
where Athena has proven difficult to install and buggy, and support for
Sixpack has also become harder.

At this point, XAS Viewer can read data from plain ASCII files or from
recent Athena Project files, but does not yet support quite as many
different file types as Athena and Sixpack -- help on this would be greatly
appreciated!  It can do basic group manipulation such as merging, and
groups and plot one or more XAFS spectra in various stages of the XAFS
normalization process and can save data to Athena Project file or save
multiple data sets to CSV files.  XAS Viewer has simple dialogs for doing
common data correction steps including recalibration, rebinning of QXAFS
data (as per a recent discussion), glitch removal, correcting
over-absorption, smoothing, and spectral deconvolution.

For analysis, XAS Viewer has a notebook panel for pre-edge subtraction and
normalization, and one for basic EXAFS processing (background removal and
Fourier transforms to chi(R)).  Its main emphasis is on visualization and
analysis of XANES spectra and so it includes panels dedicated to fitting
pre-edge peaks, Linear Combination analysis, and Principal Component
Analysis. Though definitely a Graphical User Interface, with forms to guide
the novice user, XAS Viewer goes out its way to do all data processing
through basic Larch commands that can be viewed, copied, and turned into
batch processing scripts.

Documentation for all of Larch  is a continual work in progress, and docs
with screenshots for XAS Viewer is at


Feedback or suggestions on this or any other aspects of Larch are most

Larch can be installed with simple installers for Windows, Mac OSX, Linux
which can be found from


At the moment, these installers all assume 64-bit operating systems and now
are built using Anaconda Python version 3.6.

If anyone needs to use Larch with 32-bit Windows please let me know.
Support for this will probably be dropped by the end of the calendar year,
but I do not know if this is necessary at all at this point.

For people using Larch from Python, it can also be installed as a "conda
package" for Anaconda Python, as with

    conda install -c GSECARS xraylarch

Currently, packages are available for Python 3.6, and packages for Python
2.7 should be available within a couple days.

Please let me know if you have any questions or problems,

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