Add a function that returns the name of a specific chemistry element. Use that...

Add a function that returns the name of a specific chemistry element. Use that function to print the names in the snapshot header.

src/chemistry/EAGLE/chemistry.h

@@ -37,6 +37,19 @@
 #include "physical_constants.h"
 #include "units.h"
 
+/**
+ * @brief Return a string containing the name of a given #chemistry_element.
+ */
+__attribute__((always_inline)) INLINE static const char*
+chemistry_get_element_name(enum chemistry_element elem) {
+
+  static const char* chemistry_element_names[chemistry_element_count] = {
+      "Hydrogen", "Helium",    "Carbon",   "Nitrogen", "Oxygen",
+      "Neon",     "Magnesium", "Silicium", "Iron"};
+
+  return chemistry_element_names[elem];
+}
+
 /**
  * @brief Sets the chemistry properties of the (x-)particles to a valid start
  * state.

src/chemistry/EAGLE/chemistry_io.h

@@ -19,6 +19,7 @@
 #ifndef SWIFT_CHEMISTRY_IO_EAGLE_H
 #define SWIFT_CHEMISTRY_IO_EAGLE_H
 
+#include "chemistry.h"
 #include "io_properties.h"
 
 /**
@@ -98,9 +99,14 @@ int chemistry_write_particles(const struct part* parts, struct io_props* list) {
  * @brief Writes the current model of SPH to the file
  * @param h_grpsph The HDF5 group in which to write
  */
-void chemistry_write_flavour(hid_t h_grpsph) {
-
-  io_write_attribute_s(h_grpsph, "Chemistry Model", "EAGLE");
+void chemistry_write_flavour(hid_t h_grp) {
+
+  io_write_attribute_s(h_grp, "Chemistry Model", "EAGLE");
+  for (int elem = 0; elem < chemistry_element_count; ++elem) {
+    char buffer[20];
+    sprintf(buffer, "Element %d", elem);
+    io_write_attribute_s(h_grp, buffer, chemistry_get_element_name(elem));
+  }
 }
 
 #endif /* SWIFT_CHEMISTRY_IO_EAGLE_H */