Add a constructor for the unit system that gets the 5 base units as direct input.

examples/main.c

@@ -590,7 +590,7 @@ int main(int argc, char *argv[]) {
 
     /* Not restarting so look for the ICs. */
     /* Initialize unit system and constants */
-    units_init(&us, params, "InternalUnitSystem");
+    units_init_from_params(&us, params, "InternalUnitSystem");
     phys_const_init(&us, params, &prog_const);
     if (myrank == 0 && verbose > 0) {
       message("Internal unit system: U_M = %e g.", us.UnitMass_in_cgs);

src/units.c

@@ -55,6 +55,25 @@ void units_init_cgs(struct unit_system* us) {
   us->UnitTemperature_in_cgs = 1.;
 }
 
+/**
+ * @brief Initialise the unit_system with values for the base units.
+ *
+ * @param us The #unit_system to initialise.
+ * @param U_M_in_cgs The mass unit in [g].
+ * @param U_L_in_cgs The length unit in [cm].
+ * @param U_t_in_cgs The time unit in [s].
+ * @param U_C_in_cgs The current unit in [A].
+ * @param U_T_in_cgs The temperature unit in [K].
+ */
+void units_init(struct unit_system* us, double U_M_in_cgs, double U_L_in_cgs,
+                double U_t_in_cgs, double U_C_in_cgs, double U_T_in_cgs) {
+  us->UnitMass_in_cgs = U_M_in_cgs;
+  us->UnitLength_in_cgs = U_L_in_cgs;
+  us->UnitTime_in_cgs = U_t_in_cgs;
+  us->UnitCurrent_in_cgs = U_C_in_cgs;
+  us->UnitTemperature_in_cgs = U_T_in_cgs;
+}
+
 /**
  * @brief Initialises the unit_system structure with the constants given in
  * the parameter file.
@@ -63,8 +82,9 @@ void units_init_cgs(struct unit_system* us) {
  * @param params The parsed parameter file.
  * @param category The section of the parameter file to read from.
  */
-void units_init(struct unit_system* us, const struct swift_params* params,
-                const char* category) {
+void units_init_from_params(struct unit_system* us,
+                            const struct swift_params* params,
+                            const char* category) {
 
   char buffer[200];
   sprintf(buffer, "%s:UnitMass_in_cgs", category);

src/units.h

@@ -28,7 +28,7 @@
 /**
  * @brief The unit system used internally.
  *
- * This structure contains the conversion factors to the 7 cgs base units to the
+ * This structure contains the conversion factors to the 5 cgs base units to the
  * internal units. It is used everytime a conversion is performed or an i/o
  * function is called.
  **/
@@ -96,8 +96,8 @@ enum unit_conversion_factor {
 };
 
 void units_init_cgs(struct unit_system*);
-void units_init(struct unit_system*, const struct swift_params*,
-                const char* category);
+void units_init_from_params(struct unit_system*, const struct swift_params*,
+                            const char* category);
 void units_init_default(struct unit_system* us,
                         const struct swift_params* params, const char* category,
                         const struct unit_system* def);