UT theoretical chemistry code forum

Dear All,
I have a question about the function of dymanalyze.pl. From the script description it is used to analyze the convergence of the dynamical matrices w.r.t displacements. In my calculation, I have two dynamial matrices generated for two displacements with the number of atoms same in both cases and I tried to use dymanalyze.pl to check for convergence. I get this error message:
Successively fit line to more and more data points, check how force constants change
-------------------------------------------------------------------------------------
reference 0.0000000000000 0.0000000000000
Illegal division by zero at /home/pg0104/vtstscripts/dymanalyze.pl line 84.

I am not sure what this error is due to?

Regards,
P.G.

If you attach your two DISPLACECAR files and two matrices, I'll see what is going wrong.

Dear Graeme,
I have attached the 4 files.

Thanks,
PG

I have not actually used this script before, so it took me a while to understand what it was doing and what was going wrong in your case. Here's what I found:

The analysis is done for all significant components of the Hessian matrices. What was a significant mode was hard-coded in the script. In your case, no such modes were found and the script crashed with a divide -by-zero error.

I've change the script so that this mode value is the second parameter. It will also terminate properly if no significant modes are found.

I'll attach the modified script here. If there are any other problems, let me know.