Named: Enable Name Reset after Constructor

src/particles/elements/mixin/named.H

@@ -27,6 +27,28 @@ namespace impactx::elements
      */
     struct Named
     {
+        /** Overwrite the name of the element
+         *
+         * @param new_name set a new name on the element
+         */
+        AMREX_GPU_HOST
+        void set_name (
+            std::string const & new_name
+        )
+        {
+            // free old name
+            if (m_name != nullptr) {
+                delete[] m_name;
+                m_name = nullptr;
+            }
+
+            // set new name
+            if (new_name.size() > 0) {
+                m_name = new char[new_name.size() + 1];
+                std::strcpy(m_name, new_name.c_str());
+            }
+        }
+
         /** A user-named element
          *
          * @param name a user defined and not necessarily unique name of the element
@@ -37,8 +59,7 @@ namespace impactx::elements
         )
         {
             if (name.has_value()) {
-                m_name = new char[name->size() + 1];
-                std::strcpy(m_name, name->c_str());
+                set_name(*name);
             }
         }
 
@@ -116,6 +137,7 @@ namespace impactx::elements
             return m_name != nullptr;
         }
 
+    private:
         // Implementation note:
         // This is used as a mixin class in elements that are copied to GPU. GPU compilers copy
         // a whole element by its sizeof(T).

src/python/elements.cpp

@@ -143,7 +143,11 @@ void init_elements(py::module& m)
     // mixin classes
 
     py::class_<elements::Named>(me, "Named")
-        .def_property_readonly("name", &elements::Named::name)
+        .def_property("name",
+            [](elements::Named & nm) { return nm.name(); },
+            [](elements::Named & nm, std::string new_name) { nm.set_name(new_name); },
+            "segment length in m"
+        )
         .def_property_readonly("has_name", &elements::Named::has_name)
     ;
 

tests/python/test_push.py

@@ -47,8 +47,14 @@ def test_element_push():
     assert pc.total_number_of_particles() == npart
 
     # init accelerator lattice
+    drift = elements.Drift(name="drift1", ds=0.25)
+    assert drift.name == "drift1"
+    # changed my mind on the name
+    drift.name = "mydrift"
+    assert drift.name == "mydrift"
+
     fodo = [
-        elements.Drift(name="drift1", ds=0.25),
+        drift,
     ]
     sim.lattice.extend(fodo)