Regarding QHA calculation about elastic

[jochym]

On 06.06.2014 03:01, lim520 wrote:

Dear Dr Jochym

i was going through the tutorial of QHA in your website
(http://nbviewer.ipython.org/gist/jochym/334b658cc8b3f6864c23) and
found the following warning.

/home/jochym/nipy/local/lib/python2.7/site-packages/qeutil/analyzers.py:293:
RuntimeWarning: overflow encountered in square
Cv=ndf_k_B_simps(e_e_dos/sinh(e)2,nu)
/home/jochym/nipy/local/lib/python2.7/site-packages/qeutil/analyzers.py:294:
RuntimeWarning: overflow encountered in exp
S=k_B(simps(2_dos_e/(exp(2_e)-1),nu)-simps(dos_(1-exp(-2e)),nu))

I got a similar warning when i was trying

Can you please let me know how to avoid this

This is normal by-product of the fitting procedure. It does not mean
that something is wrong - just the fitting parameters on the trial
function went out of allowed range. It is however always recommended to
carefully inspect the output. You can treat this as a signal that the
fitting is not very well determined and thus you need to be careful with
the results.

P.

[jochym]

This is actually connected with qe-util and qe-doc. Not with Elastic I believe.

[lim520]

Dear Dr.Jochym

Thank you for the reply
and sorry for using the wrong module
With regards
Linu

[jochym]

On 06.06.2014 22:34, lim520 wrote:

Dear Dr.Jochym

Thank you for the reply
and sorry for using the wrong module

No problem. The actual reason is not a very good choice of formula -
exp()^2 tands
to easily overflow the floating point range. I may transform it to some
other form in the future to avoid such confusion.

P.