Removed scale_zeta from update_delta

Author: giadarol

xtrack/beam_elements/elements_src/lineartransfermatrix.h

@@ -104,10 +104,8 @@ void LinearTransferMatrix_track_local_particle(LinearTransferMatrixData el, Loca
             new_zeta = cos_s*tmp+beta_s*sin_s*new_delta;
             new_delta = -sin_s*tmp/beta_s+cos_s*new_delta;
 
-            // We need to set zeta after updating delta
-	    // not to introduce an artificial change
-            LocalParticle_update_delta(part, new_delta);
             LocalParticle_set_zeta(part, new_zeta);
+            LocalParticle_update_delta(part, new_delta);
 	}
 
         // Change energy without change of reference momentume

xtrack/particles/particles.py

@@ -360,9 +360,6 @@ def gen_local_particle_api(mode='no_local_copy'):
 
     LocalParticle_set_delta(part, new_delta_value);
 
-    LocalParticle_scale_zeta(part,
-        rvv / LocalParticle_get_rvv(part));
-
     LocalParticle_set_rvv(part, rvv );
     LocalParticle_set_rpp(part, rpp );
     LocalParticle_set_psigma(part, psigma );