Error: roundoff error prevents tolerance from being achieved. Default GSL error handler invoked.

From: Swati Gavas <ph18016_at_iisermohali.ac.in>
Date: Wed, 30 Jun 2021 14:34:57 +0530

Dear all,
I am trying to run power-law(pk(k)=Ak^n) models in EdS cosmology with
Gadget4.
It gave me the following error for n=-1.8 and beyond (Specifically
-1.8,-2.0,-2.2, and -2.5).

ERROR: roundoff error prevents tolerance from being achieved
Default GSL error handler invoked.

or sometimes

ERROR: maximum number of subdivisions reachedDefault GSL error handler
invoked.

The input power spectrum is given for log10(k) range [-3,3].
On diagnosis, I have found two ways to get rid of it.
First, a solution is to just comment out the part where variance.txt is
written since it is not required for further code execution.
Second, the error is arising because setting epsrel=0 in
gsl_integration_qag is not working. Thus, Setting it to 5x10^-4 gets rid of
the error. Also, increasing the worksize also allows to further push this
value to 5x10^-6.

~Swati Gavas
Received on 2021-06-30 11:05:21