[Ifeffit] wavelet transforms for EXAFS

Clark Adam Hugh (PSI) adam.clark at psi.ch
Tue Aug 14 02:37:49 CDT 2018


Hi Matt

I recently had some problems incorporating the larch Cauchy wavelet transform into my program for rapid bulk processing of QEXAFS data (discussed http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2014-April/007250.html). I particular after importing the relevant module into python the cauchy_wavelet(cwsam, kweight=kwwt, _larch=mylarch) function raises the error 'not callable'. As a work around I have explicitly copied the module code for the definition into my own script and this seems to resolve the issue. I also notice that at present that it is not possible to apply a windowing function within the wavelet transform, is this just a case of windowing the K space data that is fed to the module? I would also have interest in trying to fit the EXAFS data in the wavelet space, has there been any progress in Larch for performing this?

As briefly discussed at the EXAFS conference another feature that I think would be very nice to include would be the possibility to use a Victoreen function for the post edge normalisation instead of a polynomial function. I also briefly discussed the application of the MBACK algorithm. Unless I am doing something incorrect, when trying to use the MBACK algorithm in Larch within python the following error is raised ' 'XrayDB' object has no attribute _getChantler'. In some cases it would be very interesting to apply the MBACK algorithm particularly when only a short data range is collected in some experiments.

Thanks
Adam Clark
__________________________________________
Paul Scherrer Institut
Adam Hugh Clark
WLGA/133
5232 Villigen PSI
Schweiz

Telefon: +41 56 310 41 51
E-Mail: adam.clark at psi.ch
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