Pyfrs writer occasionally failing

General
1

Hello all,

I am experiencing failures from the writer function occasionally. For instance, once I have -

[soln-plugin-writer]
dt-out = 50
basedir = .
basename = concaveTower_{t:04.0f}

  • in the ini file, and this simulation started from t=1800. It supposed to write out a file at t=1850 but nothing was written.

Another time I had dt-out = 20, the simulation only wrote out properly until t=60. After that simulation carried on but no pyfrs file wrote out.

In both cases I am sure the simulation runs ok because the velocity and pressure probes wrote out properly.

Is anyone experiencing the same issue?

Junting Chen

2

Hi Junting,

With dual integrator, in certain circumstances the physical time counter can accumulate round-off error and if the error exceeds 5e-12 at an output time, the writer plugin does not realise it needs to write. As you said, the simulation should run ok and this bug only affects the writer plugin with dual integrator.

For now please use the attached patch which forces the output at the next physical time-step. I will submit a fix to this asap.

Thanks,

Niki

0001-Writer-patch.patch (3.48 KB)

3

Thanks for the quick response!

Junting Chen

4

Hello Junting,

Did you implement the patch proposed by Niki. I am trying to do this, but I am not sure which folders/files I have to change. After the changes, is it necessary to recompile pyFR? Can you help me?

Thank you.

5

Hello Douglas,

Yes I did implement the patch.

No, you dont need to recompile pyfr. I think what i did was dropping the patch file in pyfr directory and simply type:

patch < 0001-Writer-patch.patch

Try it, everything works great so far. Thanks Niki.

Best regards,

Junting Chen