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--- software:fitallb [2020/01/15 09:02]
matthias
+++ software:fitallb [2020/04/08 08:09] (current)
matthias [Evaluating the results]
@@ Line 36: / Line 36: @@
 ===== Usage =====
-==== Running FitAllB ====
+==== Prerequisites ====
 ''fitallb.py'' is the script that allows you to refine grain positions and orientations and to compute the strain tensor in the sample. To make it work, you need :
   * the GrainSpotter output file (''.log'')
@@ Line 44: / Line 44: @@
   * optionally, a //res// file, but i don't really know what that is so I don't use it;
   * the input file (''.inp'')
+It furthermore requires //PolyXSim// and //Iminuit//. Both can be downloaded with //Anaconda// or is found on //GitHub//.
 The input file should have this look :
@@ Line 86: / Line 88: @@
 </code>
+==== Modifying the parameters ====
+Now, about the parameters of the refinement, these are the four lines starting with ''rej_'' and ''min_refl'' (maybe also the ''tol_grain'' line but it didn't do much in my tests..).
+''rej_ia'' is for internal angle, meaning the difference between the position of the measured peak and the position of the corresponding theoretical peak. In my data, I had a hard time decreasing it below 2° but I read that C. Langrand happened to have a maximum of 0.2° in internal angle misorientation.
+''rej_vol'' is linked to the intensity relativly to the volume of the grain (?). This means that the peaks have a too weak intensity. By default, it is set to 10 but I needed to increase it for my data. I succeeded in increasing up to 41 before //FitAllB// crashed (and it still rejected a lot of peaks because of intensity).
+''rej_resmean'' and ''rej_resmedian'' define, how strong a single peak is allowed to be compared to the mean/median intensity of a certain grain. If you use the value ''10'' it means that any peak, which is more than 10 times higher intensity compared to the mean/median peak intensity of that grain, is rejected.
+''min_refl'' is the minimum number of peaks you need to validate a grain. As it is a refinement step, during each run the grains will loose the "bad" peaks. If they go below the min_refl threshold, they are rejected. Check your //log-file// before the refinement to see, how many peaks are usually there to make a grain.
+==== Running the refinement ====
 Edit this input file to your purposes (modify file names, experimental conditions, crystallographic info, ...) and then type this to your command line:
@@ Line 98: / Line 112: @@
 The ''_rej'' files list all the peaks rejected during the refinement and tell you why they were rejected. Most of the time it is a problem of intensity or internal angle (marked with ''ia'').
-Now, about the parameters of the refinement, these are the four lines starting with ''rej_'' and ''min_refl'' (maybe also the ''tol_grain'' line but it didn't do much in my tests..).
+=== Reported crashs ===
+  * __maximum call reached__: Happens when //FitAllB// needs too much refinement loops to complete the calculation and is not powerfull enough to do it completly (?). Decrease your //rej_ia//, //rej_vol// or increase //min_refl// to fix it.
+  * __singular matrix__: Mean that fitallb does not have enough information on a grain to refine stress tensor. But same as before, decrease your //rej_ia//, //rej_vol// or increase //min_refl// to fix it. You can also solve this by removing the 'bad' grain in your input //log file//.
+  * __ValueError: invalid literal for int() with base 10: 'x,'__ (with x = any number): This happens when you use log-files, which were produced by merging several other log-files with //timelessGrainspotterMerge.py//. The problem can be solved when you search the log-file for two empty lines in a row and reduce them to one. The value of x gives you the grain number where to search for this in the log-file.
+  * Issues with the CIF file: Tip: If one (or multiple) of the following errors occur over and over again and you don't know what causes the error, there's a trick: Go to [[https://stokes.byu.edu/iso/isocif.php|ISOCIF]] and recreate your CIF file. If you have already a (not working) CIF file, this procedure takes only 2 minutes. In the ISOCIF output you have to modify the //symmetry_space_group_name_HM// according to the list provided [[https://github.com/FABLE-3DXRD/xfab/blob/master/xfab/sg.py|here]] and add this section:
-''rej_ia'' is for internal angle, meaning the difference between the position of the measured peak and the position of the corresponding theoretical peak. In my data, I had a hard time decreasing it below 2° but I read that C. Langrand happened to have a maximum of 0.2° in internal angle misorientation.
+  loop_
+  _atom_type_symbol
+  _atom_type_description
+  'Mg' 'Mg'
+  'Fe' 'Fe'
+  'O' 'O'
-''rej_vol'' is linked to the intensity relativly to the volume of the grain (?). This means that the peaks have a too weak intensity. By default, it is set to 10 but I needed to increase it for my data. I succeeded in increasing up to 41 before //FitAllB// crashed (and it still rejected a lot of peaks because of intensity).
+  * If you don't want to use ISOCIF, here are some ways to deal with all the issues individually:
+    * CIF-file issue: __KeyError: u'No such item: _atom_type_symbol'__: Your CIF-file is required to have both ''_atom_type_symbol'' and ''_atom_site_type_symbol''. If one of them is missing, this error will pop up. Check other CIF-files to see how to implement these two things.
-''rej_resmean'' and ''rej_resmedian'' are refined quantity (as I understand it, it corresponds to how important the correction //FitAllB// needs to do during the refinement is) and should be as small as possible. The difference between the two is the reference they used: ''rej_resmedian'' rejects peaks that contribute to the residual by a value more than ten times the median; ''rej_resmean'' rejects peaks that contribute to the residual by a value ten times higher the mean.
+    * CIF-file issue: __UnboundLocalError: local variable 'cf' referenced before assignment__: Again the CIF-file: Some old CIF-files contain ''_chemical_formula_sum'' twice (not sure why), one of them empty. Delete the empty one and try again.
+    * CIF-file issue: __KeyError: u'p4mnm'__ (or similar): It means that FitAllB cannot read the space group indicated in the CIF-file (wrong abbreviation). If you want to know, how your space group is abbreviated in a way that FitAllB can read it, check here: https://github.com/FABLE-3DXRD/xfab/blob/master/xfab/sg.py By the way: It is not case sensitive and ignores space.
-''min_refl'' is the minimum number of peaks you need to validate a grain. As it is a refinement step, during each run the grains will loose the "bad" peaks. If they go below the min_refl threshold, they are rejected.
+    * CIF-file issue: __UnboundLocalError: local variable 'unit_cell' referenced before assignment__: You probably have a typo in your crystal system (in your input file). I got rid of it, after I changed "orthorombic" to "orthorhombic".
+  * __TypeError: 'NoneType' object has no attribute '_getitem_'__ This error appears during the actual refinement of certain grains. Sometimes it can happen quite late in the refinement (on grain 300 or so), which makes it annoying, when the refinement is running over night and you only realize it next morning. There are two solutions for this: 1) Simply run //FitAllB// again and hope it works this time (sometimes it does actually). 2) If the error comes again and again at the very same grain, you have to delete that grain from the //log-file//. Normally, this would get you in trouble with the numbering, since the consecutive order of the grains gets destroyed, so you need to re-create the //log-file//. To avoid doing this every time when you run into this error, there is a trick: Simply don't delete all of the grain's information but just the majority. For example, keep one peak of the grain. This way, //FitAllB// will skip the grain in the refinement because one peak is lower than any number you usually put in the input file under //min_refl//. Run //FitAllB// again afterwards. Sometimes, you may have to delete several grains until it works.
-=== Reported crashs ===
+  * __LinAlgError: Singular matrix__ Use the same strategy as for the previous error in this list: Simply run //FitAllB// again and, if this doesn't work, make the software skip the grain by deleting most of the peaks for that particular grain.
-  * I don't remember the exact error message, but it happens that //FitAllB// says it can't read the input file. Most of the time it come from a typo in the called files name or because the file called is not in the current folder.
-  * "maximum call reached": Happens when //FitAllB// needs too much refinement loops to complete the calculation and is not powerfull enough to do it completly (?). Decrease your //rej_ia//, //rej_vol// or increase //min_refl// to fix it.
-  * "singular matrix": No idea what it means... But same as before, decrease your //rej_ia//, //rej_vol// or increase //min_refl// to fix it.
 ==== Fitgloball ====

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