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cpp/particles/interpolation/abstract_particle_set.hpp

@@ -139,6 +139,10 @@ class abstract_particle_set
                 particle_rnumber *result) = 0;
 
         // apply p2p kernel
+        // IMPORTANT: this method shuffles particle arrays.
+        // If you need some data to be shuffled according to the same permutation,
+        // please place it in `additional_data`.
+        // This applies for instance to rhs data during time steps.
         template <int state_size,
                   class p2p_kernel_class>
         int applyP2PKernel(