You really need to know the number of actual data points, which must come from the actual data. You should also know the experimental uncertainties of each point.
Most standard procedures map the actual data to a uniform grid, sometimes with smoothing of the original data. Then the information content is lost. We are doing final testing on some general routines to address this and will make them available soon. -------------------------------------------------------------------------------------- Christopher Chantler, Professor, FAIP, Fellow American Physical Society Editor-in-Chief, Radiation Physics and Chemistry Chair, International IUCr Commission on XAFS President, International Radiation Physics Society School of Physics, University of Melbourne Parkville Victoria 3010 Australia +61-3-83445437 FAX +61-3-93474783 chant...@unimelb.edu.au<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=mailto%3achantler%40unimelb.edu.au> chant...@me.com<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=mailto%3achantler%40me.com> http://optics.ph.unimelb.edu.au/~chantler/xrayopt/xrayopt.html<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=http%3a%2f%2foptics.ph.unimelb.edu.au%2f%7echantler%2fxrayopt%2fxrayopt.html> http://optics.ph.unimelb.edu.au/~chantler/home.html<https://owa.unimelb.edu.au/owa/redir.aspx?C=c7BoS0kVVkC1_S95-9x9l5cBu6YTjdAITgSrfUpfDAUV5oUH1LFYBcz08w8xvHMJoosZRdagfQM.&URL=http%3a%2f%2foptics.ph.unimelb.edu.au%2f%7echantler%2fhome.html> ________________________________ From: Ifeffit <ifeffit-boun...@millenia.cars.aps.anl.gov> on behalf of ifeffit-requ...@millenia.cars.aps.anl.gov <ifeffit-requ...@millenia.cars.aps.anl.gov> Sent: Tuesday, 11 April 2017 3:00:02 AM To: ifeffit@millenia.cars.aps.anl.gov Subject: Ifeffit Digest, Vol 170, Issue 7 Send Ifeffit mailing list submissions to ifeffit@millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-requ...@millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-ow...@millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Information content from Athena for Hamilton test? (Will Bennett) 2. Re: Information content from Athena for Hamilton test? (Wayne Lukens) ---------------------------------------------------------------------- Message: 1 Date: Mon, 10 Apr 2017 13:59:36 +1000 From: Will Bennett <w.benn...@griffith.edu.au> To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] Information content from Athena for Hamilton test? Message-ID: <CAA5p-7P__WKyB6Hzf4bUkd6=+myeevgc967p+3hdcsqavy8...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hi everyone, Just a quick question regarding the "Information Content" output in Athena's LCF window. I've recently been playing around with using the Hamilton test (as outlined in Scott Calvin's book "XAFS for Everyone") to interrogate my combinatorics results. As many of you will know, this requires an estimate of the number of independent measurements in the data, in order to determine the degrees of freedom and subsequently the "a" value for computing the Lower Incomplete Beta Function. Would Athena's value for "Information Content" be appropriate to use as an estimate of the number of independent measurements in this case? How is this value of "Information Content" determined in Athena? Thanks in advance. Will -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20170410/7d965b9d/attachment-0001.html> ------------------------------ Message: 2 Date: Mon, 10 Apr 2017 08:00:46 -0700 From: Wayne Lukens <wwluk...@lbl.gov> To: XAFS Analysis using Ifeffit <ifeffit@millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] Information content from Athena for Hamilton test? Message-ID: <CAKMihFcRgyCH1DN4ARn=_3jynpiy3ebd8jikfmzahxwuev2...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" HI Will, I am not entirely sure how this value is determined in Athena, but the number of independent data in a XANES fit is the data range divided by the resolution. If you have a spectrum with a strong pre-edge peak, you can determine the resolution from its width. Otherwise, the resolution is a convolution of the core-hole broadening and the beamline energy resolution. Athena gives a value that is very close to the value determined directly from the width of a preedge peak. Sincerely, Wayne On Sun, Apr 9, 2017 at 8:59 PM, Will Bennett <w.benn...@griffith.edu.au> wrote: > Hi everyone, > > Just a quick question regarding the "Information Content" output in > Athena's LCF window. I've recently been playing around with using the > Hamilton test (as outlined in Scott Calvin's book "XAFS for Everyone") to > interrogate my combinatorics results. As many of you will know, this > requires an estimate of the number of independent measurements in the data, > in order to determine the degrees of freedom and subsequently the "a" value > for computing the Lower Incomplete Beta Function. Would Athena's value for > "Information Content" be appropriate to use as an estimate of the number of > independent measurements in this case? How is this value of "Information > Content" determined in Athena? > > Thanks in advance. > > Will > > _______________________________________________ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit > > -- Wayne Lukens Staff Scientist Lawrence Berkeley National Lab -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20170410/f7398863/attachment-0001.html> ------------------------------ Subject: Digest Footer _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit ------------------------------ End of Ifeffit Digest, Vol 170, Issue 7 ***************************************
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