push_particles_1vb: -find_idx_pos_1st_rel

Author: JamesMcClung

src/libpsc/psc_push_particles/push_particles_1vb.hxx

@@ -60,10 +60,8 @@ struct PushParticlesVb
         auto v = advance.calc_v(prt.u());
         advance.push_x(prt.x(), v);
 
-        Int3 final_index;
-        Real3 final_pos_normalized;
-        find_idx_pos_1st_rel(prt.x(), dxi, final_index, final_pos_normalized,
-                             real_t(0.));
+        Real3 final_pos_normalized = prt.x() * dxi;
+        Int3 final_index = final_pos_normalized.fint();
 
         // CURRENT DENSITY BETWEEN (n+.5)*dt and (n+1.5)*dt
         int lg[3];