Remove unnecessary parameter in the quick Lyman-alpha cooling model

src/cooling/QLA/cooling.c

@@ -718,12 +718,6 @@ void cooling_init_backend(struct swift_params *parameter_file,
   cooling->He_reion_heat_cgs =
       parser_get_param_float(parameter_file, "QLACooling:He_reion_eV_p_H");
 
-  /* Optional parameters to correct the abundances */
-  cooling->Ca_over_Si_ratio_in_solar = parser_get_opt_param_float(
-      parameter_file, "QLACooling:Ca_over_Si_in_solar", 1.f);
-  cooling->S_over_Si_ratio_in_solar = parser_get_opt_param_float(
-      parameter_file, "QLACooling:S_over_Si_in_solar", 1.f);
-
   /* Convert H_reion_heat_cgs and He_reion_heat_cgs to cgs
    * (units used internally by the cooling routines). This is done by
    * multiplying by 'eV/m_H' in internal units, then converting to cgs units.
@@ -832,7 +826,9 @@ void cooling_restore_tables(struct cooling_function_data *cooling,
  */
 void cooling_print_backend(const struct cooling_function_data *cooling) {
 
-  message("Cooling function is 'Quick Lyman-alpha (EAGLE with primordial Z)'.");
+  message(
+      "Cooling function is 'Quick Lyman-alpha (EAGLE with primordial Z "
+      "only)'.");
 }
 
 /**

src/cooling/QLA/cooling_rates.h

@@ -36,17 +36,17 @@
  *
  * The quick Lyman-alpha chemistry model does not track any elements.
  * We use the primordial H and He to fill in the element abundance
- * array. 
+ * array.
  *
  * We also re-order the elements such that they match the order of the
  * tables. This is [H, He, C, N, O, Ne, Mg, Si, S, Ca, Fe].
- * 
+ *
  * The solar abundances table (from the cooling struct) is arranged as
  * [H, He, C, N, O, Ne, Mg, Si, S, Ca, Fe].
  *
  * @param p Pointer to #part struct.
  * @param cooling #cooling_function_data struct.
- * @param phys_const the physical constants in internal units 
+ * @param phys_const the physical constants in internal units
  * @param ratio_solar (return) Array of ratios to solar abundances.
  */
 __attribute__((always_inline)) INLINE static void abundance_ratio_to_solar(

src/cooling/QLA/cooling_struct.h

@@ -83,12 +83,6 @@ struct cooling_function_data {
   /*! Have we already done H reioisation? */
   int H_reion_done;
 
-  /*! Ca over Si abundance divided by the solar ratio for these elements */
-  float Ca_over_Si_ratio_in_solar;
-
-  /*! S over Si abundance divided by the solar ratio for these elements */
-  float S_over_Si_ratio_in_solar;
-
   /*! Redshift of He reionization */
   float He_reion_z_centre;