New Element: Marker

src/particles/elements/All.H

@@ -23,6 +23,7 @@
 #include "ExactDrift.H"
 #include "ExactSbend.H"
 #include "Kicker.H"
+#include "Marker.H"
 #include "Multipole.H"
 #include "Empty.H"
 #include "NonlinearLens.H"
@@ -60,6 +61,7 @@ namespace impactx
         ExactDrift,
         ExactSbend,
         Kicker,
+        Marker,
         Multipole,
         NonlinearLens,
         Programmable,

src/particles/elements/Empty.H

@@ -35,8 +35,8 @@ namespace impactx
 
         /** Push all particles - nothing to do here */
         void operator() (
-                ImpactXParticleContainer & /* pc */,
-                int /* step */
+            ImpactXParticleContainer & /* pc */,
+            int /* step */
         ) {
             // nothing to do
         }
@@ -62,14 +62,14 @@ namespace impactx
          */
         AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
         void operator() (
-                [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT x,
-                [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT y,
-                [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT t,
-                [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT px,
-                [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT py,
-                [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT pt,
-                [[maybe_unused]] uint64_t & AMREX_RESTRICT idcpu,
-                [[maybe_unused]] RefPart const & refpart
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT x,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT y,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT t,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT px,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT py,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT pt,
+            [[maybe_unused]] uint64_t & AMREX_RESTRICT idcpu,
+            [[maybe_unused]] RefPart const & refpart
         ) const
         {
             // nothing to do

src/particles/elements/Marker.H

@@ -0,0 +1,84 @@
+/* Copyright 2022-2023 The Regents of the University of California, through Lawrence
+ *           Berkeley National Laboratory (subject to receipt of any required
+ *           approvals from the U.S. Dept. of Energy). All rights reserved.
+ *
+ * This file is part of ImpactX.
+ *
+ * Authors: Axel Huebl
+ * License: BSD-3-Clause-LBNL
+ */
+#ifndef IMPACTX_ELEMENT_MARKER_H
+#define IMPACTX_ELEMENT_MARKER_H
+
+#include "particles/ImpactXParticleContainer.H"
+#include "mixin/thin.H"
+#include "mixin/nofinalize.H"
+
+#include <AMReX_Extension.H>
+#include <AMReX_REAL.H>
+
+
+namespace impactx
+{
+    struct Marker
+    : public elements::Thin,
+      public elements::NoFinalize
+    {
+        static constexpr auto name = "Marker";
+        using PType = ImpactXParticleContainer::ParticleType;
+
+        /** This element does nothing.
+         */
+        Marker ()
+        {
+        }
+
+        /** Push all particles - nothing to do here */
+        void operator() (
+            ImpactXParticleContainer & /* pc */,
+            int /* step */
+        ) {
+            // nothing to do
+        }
+
+        /** Push all particles - nothing to do here */
+        void operator() (
+            ImpactXParticleContainer::iterator & /* pti */,
+            RefPart & AMREX_RESTRICT /* ref_part */
+        ) {
+            // nothing to do
+        }
+
+        /** Does nothing to a particle.
+         *
+         * @param x particle position in x
+         * @param y particle position in y
+         * @param t particle position in t
+         * @param px particle momentum in x
+         * @param py particle momentum in y
+         * @param pt particle momentum in t
+         * @param idcpu particle global index (unused)
+         * @param refpart reference particle
+         */
+        AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+        void operator() (
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT x,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT y,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT t,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT px,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT py,
+            [[maybe_unused]] amrex::ParticleReal & AMREX_RESTRICT pt,
+            [[maybe_unused]] uint64_t & AMREX_RESTRICT idcpu,
+            [[maybe_unused]] RefPart const & refpart
+        ) const
+        {
+            // nothing to do
+        }
+
+        /** This pushes the reference particle. */
+        using Thin::operator();
+    };
+
+} // namespace impactx
+
+#endif // IMPACTX_ELEMENT_MARKER_H

src/python/elements.cpp

@@ -730,18 +730,31 @@ void init_elements(py::module& m)
     ;
     register_beamoptics_push(py_Multipole);
 
-    py::class_<Empty, elements::Thin> py_None(me, "Empty");
-    py_None
+    py::class_<Empty, elements::Thin> py_Empty(me, "Empty");
+    py_Empty
         .def("__repr__",
-             [](Empty const & /* none */) {
+             [](Empty const & /* empty */) {
                  return std::string("<impactx.elements.Empty>");
              }
         )
         .def(py::init<>(),
              "This element does nothing."
         )
     ;
-    register_beamoptics_push(py_None);
+    register_beamoptics_push(py_Empty);
+
+    py::class_<Marker, elements::Thin> py_Marker(me, "Marker");
+    py_Marker
+            .def("__repr__",
+                 [](Marker const & /* marker */) {
+                     return std::string("<impactx.elements.Marker>");
+                 }
+            )
+            .def(py::init<>(),
+                 "This element does nothing."
+            )
+            ;
+    register_beamoptics_push(py_Marker);
 
     py::class_<NonlinearLens, elements::Thin, elements::Alignment> py_NonlinearLens(me, "NonlinearLens");
     py_NonlinearLens