Discrepancy between total mass of the merger product between merged_mixed.txt and merger_unmixed.txt [minor issue]

[JRGarza]

Hi,

While trying out the code, I noticed a discrepancy in the reported final mass of the merger product.

As an example, I am considering a merger between 500 and 50 Msun stars, using the following parameters:

 {
                      'n_target_shells': 400, 
                      'enable_mixing': True, 
                      'mixing_shells': 400, 
                      'enable_remeshing': False, 
                      'remeshing_shells': 400, 
                      'enable_shock_heating': True, 
                      'f_mod': 1.0, 
                      'relaxation_profiles': True, 
                      'extrapolate_shock_heating': True, 
                      'initial_buoyancy': False, 
                      'final_buoyancy': False, 
                      'chemical_species': ['neut', 'h1', 'h2', 'he3', 'he4', 'li7', 'be7', 'b8', 'c12', 'c13', 'n13', 'n14', 'n15', 'o16', 'o17', 'o18', 'f19', 'ne20', 'ne21', 'ne22', 'na21', 'na22', 'na23', 'mg24', 'mg25', 'mg26', 'al25', 'al26', 'al27'], 
                      'fill_missing_species': False, 
                      'massloss_fraction': 0.0, 
                      'output_diagnostics': True
}

The merger product mass reported in the merged_mixed.txt file is:
# star_mass = 549.8596538253582366

While in the merged_unmixed.txt file is:
# star_mass = 550.6768758399820172

Where the latter one is consistent with the addition of both masses, as no mass loss is considered.

This is a minor issue, the discrepancy of the masses vary depending on the models I consider for the merger but it remains minimal.