Mistakes in metallity calculations

[MatthieuSchaller]

We identified two issues when computing the metallicities of substructures.

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First one is a missing normalisation of the aperture-based total-gas Z.

This patch should fix it:

diff --git a/src/substructureproperties.cxx b/src/substructureproperties.cxx
index f5da189..3fd8a0f 100644
--- a/src/substructureproperties.cxx
+++ b/src/substructureproperties.cxx
@@ -5580,7 +5580,7 @@ void CalculateApertureQuantities(Options &opt, Int_t &ning, Particle *Part, Prop
             if (EncMassGas>0) pdata.aperture_vrdisp_gas[iaptindex]=EncVRDispGas/EncMassGas;
 #ifdef STARON
             pdata.aperture_SFR_gas[iaptindex]=EncSFR;
-            pdata.aperture_Z_gas[iaptindex]=EncZmetGas;
+            pdata.aperture_Z_gas[iaptindex]=EncZmetGas/EncMassGas;
             pdata.aperture_npart_gas_sf[iaptindex]=NinsideGasSF;
             pdata.aperture_npart_gas_nsf[iaptindex]=NinsideGasNSF;
             pdata.aperture_mass_gas_sf[iaptindex]=EncMassGasSF;

Basically, the value returned is \sum m_i Z_i with the division by \sum m_i at the end missing.
This is done correctly for the SFing and NSFing sub-components, however.

I haven't checked whether there are other similar problems but all the other outputs look correct when looking at our pipeline plots.

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Second one is related to OpenMP and non-aperture quantities.
It seems that at least Zmet_gas and Mass_gas are not calculated correctly when running with OpenMP.

This plot shows the issue:

We'd expect Mass_gas to be Mass_gas_sf + Mass_gas_nsf.
This problem then translates into incorrect Z for the total.

If I switch off openMP then the problem is not there any more.

I think this means there is a problem with the private variables used for this calculation.
There might also be additional problems with other quantities; we haven't checked everything.

[MatthieuSchaller]

The projected aperture metallicites also seem to be weird. But I couldn't come up with a sensible patch; I don't understand well enough how this whole code section works.