Ensure not to allocate if size is zero

bfps/cpp/particles/abstract_particles_output.hpp

@@ -176,7 +176,7 @@ public:
                     buffer_particles_rhs_send[idx_rhs].reset(new real_number[size_buffers_send*buffers_size_particle_rhs_send]);
                 }
             }
-            else if(buffers_size_particle_rhs_send < size_particle_rhs && size_particle_rhs > 0){
+            else if(buffers_size_particle_rhs_send < size_particle_rhs && size_particle_rhs > 0 && size_buffers_send > 0){
                 buffers_size_particle_rhs_send = size_particle_rhs;
                 for(int idx_rhs = 0 ; idx_rhs < nb_rhs ; ++idx_rhs){
                     buffer_particles_rhs_send[idx_rhs].reset(new real_number[size_buffers_send*buffers_size_particle_rhs_send]);