Test 125

Added a new test to help @jwillis with vectorization.

The old tests are now more thorough as well.

src/hydro/Default/hydro.h

@@ -20,6 +20,8 @@
 #include "adiabatic_index.h"
 #include "approx_math.h"
 
+#include <float.h>
+
 /**
  * @brief Computes the hydro time-step of a given particle
  *
@@ -263,3 +265,39 @@ __attribute__((always_inline)) INLINE static float hydro_get_internal_energy(
 
   return p->u;
 }
+
+/**
+ * @brief Returns the pressure of a particle
+ *
+ * @param p The particle of interest
+ * @param dt Time since the last kick
+ */
+__attribute__((always_inline)) INLINE static float hydro_get_pressure(
+    const struct part *restrict p, float dt) {
+
+  return p->force.P_over_rho2 * p->rho * p->rho / p->rho_dh;
+}
+
+/**
+ * @brief Returns the entropy of a particle
+ *
+ * @param p The particle of interest
+ * @param dt Time since the last kick
+ */
+__attribute__((always_inline)) INLINE static float hydro_get_entropy(
+    const struct part *restrict p, float dt) {
+
+  return hydro_gamma_minus_one * p->u * pow_minus_gamma_minus_one(p->rho);
+}
+
+/**
+ * @brief Returns the sound speed of a particle
+ *
+ * @param p The particle of interest
+ * @param dt Time since the last kick
+ */
+__attribute__((always_inline)) INLINE static float hydro_get_soundspeed(
+    const struct part *restrict p, float dt) {
+
+  return p->force.soundspeed;
+}