Added more conversion functions from comoving to physical for the thermodynamic quantities.

.gitignore

@@ -48,6 +48,7 @@ tests/swift_dopair_standard.dat
 tests/brute_force_perturbed.dat
 tests/swift_dopair_perturbed.dat
 tests/test27cells
+tests/test27cells_subset
 tests/testPeriodicBC
 tests/test125cells
 tests/brute_force_27_standard.dat

src/cosmology.c

@@ -137,7 +137,7 @@ void cosmology_update(struct cosmology *c, integertime_t ti_current) {
   c->a = a;
   c->a_inv = a_inv;
   c->a3_inv = a_inv * a_inv * a_inv;
-  c->a_factor_sig_vel =
+  c->a_factor_sound_speed =
       pow(a, -1.5 * hydro_gamma_minus_one); /* a^{3*(1-gamma)/2} */
   c->a_factor_grav_accel = a_inv * a_inv;   /* 1 / a^2 */
   c->a_factor_hydro_accel =
@@ -458,7 +458,7 @@ void cosmology_init_no_cosmo(const struct swift_params *params,
   c->a = 1.;
   c->a_inv = 1.;
   c->a3_inv = 1.;
-  c->a_factor_sig_vel = 1.;
+  c->a_factor_sound_speed = 1.;
   c->a_factor_hydro_accel = 1.;
   c->a_factor_grav_accel = 1.;
 

src/cosmology.h

@@ -41,8 +41,8 @@ struct cosmology {
   /*! Inverse cube of the current expansion factor of the Universe */
   double a3_inv;
 
-  /*! Power of the scale-factor used for signal-velocity conversion */
-  double a_factor_sig_vel;
+  /*! Power of the scale-factor used for sound-speed conversion */
+  double a_factor_sound_speed;
 
   /*! Power of the scale-factor used for gravity accelerations */
   double a_factor_grav_accel;

src/hydro/Gadget2/hydro.h

@@ -42,7 +42,7 @@
 #include "minmax.h"
 
 /**
- * @brief Returns the internal energy of a particle
+ * @brief Returns the comoving internal energy of a particle
  *
  * @param p The particle of interest
  */
@@ -53,7 +53,7 @@ hydro_get_comoving_internal_energy(const struct part *restrict p) {
 }
 
 /**
- * @brief Returns the internal energy of a particle
+ * @brief Returns the physical internal energy of a particle
  *
  * @param p The particle of interest.
  * @param cosmo The cosmological model.
@@ -66,16 +66,27 @@ hydro_get_physical_internal_energy(const struct part *restrict p,
 }
 
 /**
- * @brief Returns the pressure of a particle
+ * @brief Returns the comoving pressure of a particle
  *
  * @param p The particle of interest
  */
-__attribute__((always_inline)) INLINE static float hydro_get_pressure(
+__attribute__((always_inline)) INLINE static float hydro_get_comoving_pressure(
     const struct part *restrict p) {
 
   return gas_pressure_from_entropy(p->rho, p->entropy);
 }
 
+/**
+ * @brief Returns the physical pressure of a particle
+ *
+ * @param p The particle of interest
+ */
+__attribute__((always_inline)) INLINE static float hydro_get_physical_pressure(
+    const struct part *restrict p, const struct cosmology *cosmo) {
+
+  return gas_pressure_from_entropy(p->rho * cosmo->a3_inv, p->entropy);
+}
+
 /**
  * @brief Returns the comoving entropy of a particle
  *
@@ -100,16 +111,29 @@ __attribute__((always_inline)) INLINE static float hydro_get_physical_entropy(
 }
 
 /**
- * @brief Returns the sound speed of a particle
+ * @brief Returns the comoving sound speed of a particle
  *
  * @param p The particle of interest
  */
-__attribute__((always_inline)) INLINE static float hydro_get_soundspeed(
-    const struct part *restrict p) {
+__attribute__((always_inline)) INLINE static float
+hydro_get_comoving_soundspeed(const struct part *restrict p) {
 
   return p->force.soundspeed;
 }
 
+/**
+ * @brief Returns the physical sound speed of a particle
+ *
+ * @param p The particle of interest
+ * @param cosmo The cosmological model.
+ */
+__attribute__((always_inline)) INLINE static float
+hydro_get_physical_soundspeed(const struct part *restrict p,
+                              const struct cosmology *cosmo) {
+
+  return cosmo->a_factor_sound_speed * p->force.soundspeed;
+}
+
 /**
  * @brief Returns the comoving density of a particle
  *
@@ -209,7 +233,7 @@ __attribute__((always_inline)) INLINE static float hydro_compute_timestep(
 
   /* CFL condition */
   const float dt_cfl = 2.f * kernel_gamma * CFL * cosmo->a * p->h /
-                       (cosmo->a_factor_sig_vel * p->force.v_sig);
+                       (cosmo->a_factor_sound_speed * p->force.v_sig);
 
   return dt_cfl;
 }

src/hydro/Gadget2/hydro_debug.h

@@ -31,7 +31,7 @@ __attribute__((always_inline)) INLINE static void hydro_debug_particle(
       p->x[0], p->x[1], p->x[2], p->v[0], p->v[1], p->v[2], xp->v_full[0],
       xp->v_full[1], xp->v_full[2], p->a_hydro[0], p->a_hydro[1], p->a_hydro[2],
       p->h, p->density.wcount, p->density.wcount_dh, p->mass, p->density.rho_dh,
-      p->rho, hydro_get_pressure(p), p->force.P_over_rho2, p->entropy,
+      p->rho, hydro_get_comoving_pressure(p), p->force.P_over_rho2, p->entropy,
       p->entropy_dt, p->force.soundspeed, p->density.div_v, p->density.rot_v[0],
       p->density.rot_v[1], p->density.rot_v[2], p->force.balsara,
       p->force.v_sig, p->force.h_dt, p->time_bin);

src/hydro/Gadget2/hydro_io.h

@@ -62,7 +62,7 @@ void convert_u(const struct engine* e, const struct part* p, float* ret) {
 
 void convert_P(const struct engine* e, const struct part* p, float* ret) {
 
-  ret[0] = hydro_get_pressure(p);
+  ret[0] = hydro_get_comoving_pressure(p);
 }
 
 void convert_part_pos(const struct engine* e, const struct part* p,

tests/test125cells.c

-
 /*******************************************************************************
  * This file is part of SWIFT.
  * Copyright (C) 2016 Matthieu Schaller (matthieu.schaller@durham.ac.uk).
@@ -411,8 +410,8 @@ void dump_particle_fields(char *fileName, struct cell *main_cell,
 #endif
             hydro_get_comoving_entropy(&main_cell->parts[pid]),
             hydro_get_comoving_internal_energy(&main_cell->parts[pid]),
-            hydro_get_pressure(&main_cell->parts[pid]),
-            hydro_get_soundspeed(&main_cell->parts[pid]),
+            hydro_get_comoving_pressure(&main_cell->parts[pid]),
+            hydro_get_comoving_soundspeed(&main_cell->parts[pid]),
             main_cell->parts[pid].a_hydro[0], main_cell->parts[pid].a_hydro[1],
             main_cell->parts[pid].a_hydro[2], main_cell->parts[pid].force.h_dt,
 #if defined(GADGET2_SPH)

tests/testInteractions.c

@@ -137,8 +137,8 @@ void dump_indv_particle_fields(char *fileName, struct part *p) {
           p->density.div_v,
 #endif
           hydro_get_comoving_entropy(p), hydro_get_comoving_internal_energy(p),
-          hydro_get_pressure(p), hydro_get_soundspeed(p), p->a_hydro[0],
-          p->a_hydro[1], p->a_hydro[2], p->force.h_dt,
+          hydro_get_comoving_pressure(p), hydro_get_comoving_soundspeed(p),
+          p->a_hydro[0], p->a_hydro[1], p->a_hydro[2], p->force.h_dt,
 #if defined(GADGET2_SPH)
           p->force.v_sig, p->entropy_dt, 0.f
 #elif defined(DEFAULT_SPH)