[Ifeffit] Running (D)Artemis yields different result from that shown in (D)Artemis instruction videos

Ravel, Bruce bravel at bnl.gov
Sun Oct 21 07:36:10 CDT 2012


I don't know what to tell you.  On the computer I am sitting in front of right now, I opened your two project files and hit the fit buttons, I get the same fit with only numerical differences.  Here I am cutting and pasting from the two log files:

old artemis:

  Chi-square                  =    4334.684537717
  Reduced Chi-square          =     691.819976095
  R-factor                    =       0.004250325

  amp             =     0.8649100   +/-      0.0412220    (1.0000)
  enot            =     5.6049380   +/-      0.2950270    (0.0000)
  delr            =    -0.0226780   +/-      0.0023790    (0.0000)
  ss              =     0.0082230   +/-      0.0003250    (0.0030)

new artemis:

  Chi-square                  : 4348.7359268
  Reduced chi-square          : 694.0625918                                        
  R-factor                    : 0.0042652   

  amp                =   0.86526150    # +/-   0.04129645     [1.00000]
  enot               =   5.61081742    # +/-   0.29527844     [0]
  delr               =  -0.02266589    # +/-   0.00238341     [0]
  ss                 =   0.00822546    # +/-   0.00032571     [0.00300]

I don't acknowledge that there is a problem.


From: ifeffit-bounces at millenia.cars.aps.anl.gov [ifeffit-bounces at millenia.cars.aps.anl.gov] on behalf of Tsuei, Ku-Ding [tsuei at nsrrc.org.tw]
Sent: Thursday, October 18, 2012 1:15 PM
To: ifeffit at millenia.cars.aps.anl.gov
Subject: [Ifeffit] Running (D)Artemis yields different result from that shown in (D)Artemis instruction videos

Hi Bruce,

I went through your (D)Artemis instruction videos and ran the latest
Demetris 0.9.12 with 0.9.13 update side by side to reproduce the
results. However, my running yields much poorer fitting results on Au
foil EXAFS, even the first shell (video 03). Actually it happened using
the older 0.9.11 too. I also went through your Lecture videos shot at
Diamond and ran (D)Artemis but could reproduce your results closely. I
have felt puzzled for quite a while why the simplest case Au foil does
work well. Today I tried to run the same Au data and fitting by the old,
last version of Artemis 0.8.014. I could produce very good fitting on
the first shell with the R-factor very near that shown in the video. I
made sure the math expressions for the fitting parameters amp, enot,
delr and ss are set exactly the same, with fitting range exactly the
same, in both programs. Their screen outputs file is attached. The saved
respective project files are also attached. I copied the fit outputs
into their journals. I would appreciate if you may review these results
and help clear my puzzle.

Best regards,


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