Modelling lattice parameters

wilmash

I have been attempting to perform a parametric rietveld refinement on a Bruker D8 variable temperature data set. The goal of this refinement is to constrain the lattice parameters by the equation specified in the article by Graham W. Stinton and John S. O. Evans.
Upon running the refinement, TOPAS displays the error message:

Uninitialized_Variable in equation: lpc_t_0005

I have tried not fitting this data set i.e. commenting out the line that says "#define use_some", but the error proceeds onto the next data set i.e. lpc_t_0006.
Thanks
Wilson

ahhill

Hi wilson.

I too am having a go at the parametric surface refinment. stuggling a little, but hope to get there. Have you tried just commenting out the following line?


#define use_t_0005

To be honest, I haven't quite got that far yet, so would be interested to hear your thoughts on setting up the inp file.

Adrian

rowlesmr

For some more help, have a look at the file topas.inp (I'm pretty sure this is what it's called...) This is the actual input file that is run after the one you've written goes through the preprocessor.

That way, you can see which things get turned on and off with the #define statements.

wilmash

Hi all

@Adrian, yes I have commented out the #define use_t_0005 line, but the error persists onto the next data set t_0006. With regards to setting up an inp file; I learned this by going through John Evans's web tutorial on surface rietveld refinements (Session 25, tutorial 34/35)

http://www.dur.ac.uk/john.evans//topas_workshop/pcg_workshop_menu.htm

Hope this will help.

@Matthew, is the file not called the topas.log under the topas directory? I could not find the topas.inp file. Certainly the topas.log file looks less messy than the inp file, and as you said helps in identifying whats turned on and off.

rowlesmr

Ah, yes.

It is topas.log