Multigroup Multiplicity Matrix Message

I am using OpenMC with multigroup cross sections and I get the following warnings.

 WARNING: 2entries in the Multiplicity Matrix were changed from 0 to 1
 WARNING: 1entries in the Multiplicity Matrix were changed from 0 to 1
 WARNING: 1entries in the Multiplicity Matrix were changed from 0 to 1
 WARNING: 1entries in the Multiplicity Matrix were changed from 0 to 1
 WARNING: 1entries in the Multiplicity Matrix were changed from 0 to 1
 WARNING: 1entries in the Multiplicity Matrix were changed from 0 to 1
 WARNING: 1entries in the Multiplicity Matrix were changed from 0 to 1

Is this something I need to be concerned about? Could you please explain what is going on here?
I have included my multigroup h5 file here as well.

Thank you!
marvel_xs.h5 (75.5 KB)

Hello @wcdawn,

This warning means that the multiplicity matrix (i.e., the value of \nu in the scattering term) was provided as a zero. Since this may have been a mistake, we alert the user to this possibility and change the value to 1.0 instead of 0.0. This should have no effect on the calculation.

Hope this helps.
Adam

@agnelson thanks for the info!

Thanks. How to provide a non-zero multiplicity matrix at the corss-section generation step in OpenMC and avoid this warning?