Typo and Parallel run issues in meshSizeObject.C

[Vigneshwaran-Sankar]

Hi,

I’ve been testing AMR libraries with reactingPimpleCentralDyMFoam and encountered the following issues:

1. Typo in meshSizeObject.C
   There appears to be a likely copy-paste typo in meshSizeObject.C, lines 103–104. Please verify if this was unintentional.

2. FPE from densityGradient estimator (from blastFoam repo)
   I compiled the densityGradient error estimator from the blastFoam repo (link), which is currently missing in blastAMR. During parallel runs, I encountered floating point exceptions (FPEs) in meshSizeObject, potentially due to unguarded operations. For example:
   Lined 122-125:

forAll(dx, celli)
{
dx[celli] = sqrt(dx[celli]/scalar(nFaces[celli]));
}

Line 115:
if (mag(Sf[facei]/magSf[facei] & validD) > 0.5)
and so on.
These could benefit from safety guards to prevent division-by-zero or undefined operations. I have attached the workaround I followed for the same.

Mod_meshSizeObject.txt