Simplifying calculation in define_central_subhalo

Only the Mvir definition is now inside the if of apply_fix_mass
swapping.

src/tree_builder.cpp

@@ -215,24 +215,27 @@ SubhaloPtr TreeBuilder::define_central_subhalo(HaloPtr &halo, SubhaloPtr &subhal
 	halo->position = subhalo->position;
 	halo->velocity = subhalo->velocity;
 
+	double mvir = subhalo->Mvir;
 
 	// calculate subhalo properties based on halo mass if number of particles is too small or in the case of applying the fix to mass swapping events:
 	if(dark_matter_params.apply_fix_to_mass_swapping_events){
-		double mvir = halo->Mvir;
-		double z= sim_params.redshifts[subhalo->snapshot];
-		double npart = mvir/sim_params.particle_mass;
+		mvir = halo->Mvir;
+	}
 
-		subhalo->concentration = darkmatterhalos->nfw_concentration(mvir, z);
+	double z= sim_params.redshifts[subhalo->snapshot];
+	double npart = mvir/sim_params.particle_mass;
 
-		if (subhalo->concentration < 1) {
-			throw invalid_argument("concentration is <1, cannot continue. Please check input catalogue");
-		}
-		subhalo->lambda = darkmatterhalos->halo_lambda(*subhalo, mvir, z, npart);
-		subhalo->Vvir = darkmatterhalos->halo_virial_velocity(mvir, z);
+	subhalo->concentration = darkmatterhalos->nfw_concentration(mvir, z);
+
+	if (subhalo->concentration < 1) {
+		throw invalid_argument("concentration is <1, cannot continue. Please check input catalogue");
 	}
+	subhalo->lambda = darkmatterhalos->halo_lambda(*subhalo, mvir, z, npart);
+	subhalo->Vvir = darkmatterhalos->halo_virial_velocity(mvir, z);
 
 	halo->concentration = subhalo->concentration;
 	halo->lambda = subhalo->lambda;
+
 	/** If virial velocity of halo (which is calculated from the total mass
 	and redshift) is smaller than the virial velocity of the central subhalo, which is
 	directly calculated in VELOCIraptor, then adopt the VELOCIraptor one.**/