Dear all,

tried the upgrade under anaconda3, on MacOs10.12.6. after the upgrade nothing 
worked any more

did the following steps:

conda update --all
conda install -yc GSECARS xraylarch
larch -m

and
pip install pyshortcuts==1.4
larch -m

nothing worked anymore. It worked again after a complete delete and re-install 
of the actual version of anaconda3

Best regards

Stefan Mangold

Am 28.02.2020 um 21:53 schrieb Matt Newville 
<newvi...@cars.uchicago.edu<mailto:newvi...@cars.uchicago.edu>>:

Hi Everyone,

Larch 0.9.47 is now available, with installers and source code at  
https://xraypy.github.io/xraylarch/installation.html.   For python users, there 
is a plain python package available on PyPI and conda packages for Anaconda 
Python.  See the installation docs for more details.

There have been several improvements and bug fixes, especially for the XAS 
Viewer application and for XRF modeling in the nearly six months since the last 
release.  In particular, there have been two improvements to basic XAFS and 
XANES data processing, both based on user reports and comparisons to older 
versions of Ifeffit/Athena and give a noticeable change in XAFS and XANES 
processing.

First, the ranges used in by the pre_edge() function for finding the edge step 
for normalization are now better determined from the actual data range rather 
than simply being hard-wired numbers.  These improvements were long over-due 
and give noticeably better default results for XANES data, especially for 
relatively low-energy edges such as S and Cl K edges.

When reading Athena Project files (say, to import into XAS Viewer), the 
pre-edge and normalization ranges from the Athena Project file will be 
preserved.  When reading in new raw data, or if you select the "Use Default 
Setting" button on the Normalization Panel for any group in XAS Viewer, the 
newer defaults will be used.   You can always alter these values, but in 
playing around with this with a range of datasets, the new defaults seem to 
give a noticeable improvement in almost all cases and rarely bad.

Second, as a few users have pointed out or gently hinted at over many months, 
there were sometimes significant differences in the background removals between 
classic Autobk/Ifeffit/Athena and Larch, with Larch sometimes being noticeably 
and inexplicably worse. I believe this involved two different problems.  One 
was introduced a while back when implementing an estimate of delta_chi - the 
variance in chi due to the background subtraction. This estimate is important, 
but I botched some of the configurations of the number of knots, fit range, and 
Rbkg. The other problem was that "spline clamps" were just done too differently 
in Larch and Ifeffit/Athena.

I believe this is now working much better: the background results are much more 
consistent, and do not occasionally get "very bad".  They also happen to be 
generally closer to Autobk/Ifeffit/Athena, and perhaps slightly better because 
the fit range in R-space is now more consistently determined (instead of 
wandering +/- a few R data points around Rbkg where the misfit will often be 
the largest). In addition, `delta_chi` (never calculated in Ifeffit/Athena) is 
now also more consistent.  One consequence of this change is that a very small 
change in Rbkg (of say 0.01 to 0.05 Ang) may actually give no difference at all 
in mu0(E) or in chi(k).

I bring these changes up because I think they will be noticeable.  I think they 
are both improvements, but let me know if you find cases for which you think 
are now made worse.   Possibly related: one thing that I definitely noticed in 
going through several example data sets was that I tended to favor a k-weight 
of 2 instead of 1 for background subtraction -- so much so that it seemed like 
this might be a better default.  I did not change this default yet, but if you 
have a strong opinion on this, that might be a good topic for discussion here.

There are some documentation improvements, but this is an ongoing process and 
never complete.  It is also one area where help and feedback would greatly be 
appreciated.  If you or your students have time to work through the larch 
examples and/or documentation and make improvements or even suggestions for 
improvements in readability or completeness, it would be greatly appreciated.

Thanks,

--Matt Newville
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