Make the cooling compatible with GIZMO as well. Added Stefan and Massimiliano to the author list.

AUTHORS

@@ -8,3 +8,5 @@ John A. Regan 		john.a.regan@durham.ac.uk
 Angus Lepper		angus.lepper@ed.ac.uk
 Tom Theuns 		tom.theuns@durham.ac.uk
 Richard G. Bower	r.g.bower@durham.ac.uk
+Stefan Arridge		stefan.arridge@durham.ac.uk
+Massimiliano Culpo	massimiliano.culpo@googlemail.com

src/cooling/const_lambda/cooling.h

@@ -72,7 +72,7 @@ __attribute__((always_inline)) INLINE static float cooling_rate(
 
   /* Get particle properties */
   /* Density */
-  const float rho = p->rho;
+  const float rho = hydro_get_density(p);
   /* Get cooling function properties */
   const float X_H = cooling->hydrogen_mass_abundance;
   /* lambda should always be set in cgs units */

src/hydro/Gizmo/hydro.h

@@ -20,6 +20,7 @@
 #include <float.h>
 #include "adiabatic_index.h"
 #include "approx_math.h"
+#include "equation_of_state.h"
 #include "hydro_gradients.h"
 #include "minmax.h"
 
@@ -502,3 +503,34 @@ __attribute__((always_inline)) INLINE static float hydro_get_density(
 
   return p->primitives.rho;
 }
+
+/**
+ * @brief Modifies the thermal state of a particle to the imposed internal
+ * energy
+ *
+ * This overrides the current state of the particle but does *not* change its
+ * time-derivatives
+ *
+ * @param p The particle
+ * @param u The new internal energy
+ */
+__attribute__((always_inline)) INLINE static void hydro_set_internal_energy(
+    struct part* restrict p, float u) {
+
+  p->conserved.energy = u;
+}
+
+/**
+ * @brief Modifies the thermal state of a particle to the imposed entropy
+ *
+ * This overrides the current state of the particle but does *not* change its
+ * time-derivatives
+ *
+ * @param p The particle
+ * @param S The new entropy
+ */
+__attribute__((always_inline)) INLINE static void hydro_set_entropy(
+    struct part* restrict p, float S) {
+
+  p->conserved.energy = gas_internal_energy_from_entropy(p->primitives.rho, S);
+}