Fixed the minimal SPH hydro version

src/debug.c

@@ -100,7 +100,7 @@ void printgParticle(struct gpart *gparts, long long int id, size_t N) {
 
 void printParticle_single(struct part *p, struct xpart *xp) {
 
-  printf("## Particle: id=%lld", p->id);
+  printf("## Particle: id=%lld ", p->id);
   hydro_debug_particle(p, xp);
 }
 

src/engine.c

@@ -1904,18 +1904,18 @@ void engine_init_particles(struct engine *e) {
 
   if (e->nodeID == 0) message("Initialising particles");
 
+  engine_prepare(e);
+
   /* Make sure all particles are ready to go */
   /* i.e. clean-up any stupid state in the ICs */
   if (e->policy & engine_policy_hydro) {
-    space_map_cells_pre(s, 1, cell_init_parts, NULL);
+    space_map_cells_pre(s, 0, cell_init_parts, NULL);
   }
   if ((e->policy & engine_policy_self_gravity) ||
       (e->policy & engine_policy_external_gravity)) {
-    space_map_cells_pre(s, 1, cell_init_gparts, NULL);
+    space_map_cells_pre(s, 0, cell_init_gparts, NULL);
   }
 
-  engine_prepare(e);
-
   engine_marktasks(e);
 
   /* Build the masks corresponding to the policy */

src/hydro/Minimal/hydro.h

@@ -172,14 +172,7 @@ __attribute__((always_inline))
 __attribute__((always_inline)) INLINE static void hydro_predict_extra(
     struct part* p, struct xpart* xp, int t0, int t1, double timeBase) {
 
-  const float dt = t1 - t0;
-
-  /* Predict internal energy */
-  const float w = p->u_dt / p->u * dt;
-  if (fabsf(w) < 0.2f)
-    p->u *= approx_expf(w); /* 4th order expansion of exp(w) */
-  else
-    p->u *= expf(w);
+  p->u = xp->u_full;
 
   /* Need to recompute the pressure as well */
   p->force.pressure = p->rho * p->u * (const_hydro_gamma - 1.f);

src/hydro/Minimal/hydro_iact.h

@@ -131,18 +131,15 @@ __attribute__((always_inline)) INLINE static void runner_iact_force(
   const float P_over_rho_j = pressurej / (rhoj * rhoj) * pj->rho_dh;
 
   /* Compute dv dot r. */
-  float dvdr = (pi->v[0] - pj->v[0]) * dx[0] + (pi->v[1] - pj->v[1]) * dx[1] +
-               (pi->v[2] - pj->v[2]) * dx[2];
-  dvdr *= r_inv;
+  const float dvdr = (pi->v[0] - pj->v[0]) * dx[0]
+                   + (pi->v[1] - pj->v[1]) * dx[1]
+                   + (pi->v[2] - pj->v[2]) * dx[2];
 
-  /* Compute the relative velocity. (This is 0 if the particles move away from
-   * each other and negative otherwise) */
-  const float omega_ij = fminf(dvdr, 0.f);
 
   /* Compute sound speeds */
   const float ci = sqrtf(const_hydro_gamma * pressurei / rhoi);
   const float cj = sqrtf(const_hydro_gamma * pressurej / rhoj);
-  const float v_sig = ci + cj + 3.f * omega_ij;
+  const float v_sig = ci + cj;
 
   /* SPH acceleration term */
   const float sph_term = (P_over_rho_i * wi_dr + P_over_rho_j * wj_dr) * r_inv;
@@ -157,8 +154,8 @@ __attribute__((always_inline)) INLINE static void runner_iact_force(
   pj->a_hydro[2] += mi * sph_term * dx[2];
 
   /* Get the time derivative for u. */
-  pi->u_dt += P_over_rho_i * mj * dvdr * wi_dr;
-  pj->u_dt += P_over_rho_j * mi * dvdr * wj_dr;
+  pi->u_dt += P_over_rho_i * mj * dvdr * r_inv * wi_dr;
+  pj->u_dt += P_over_rho_j * mi * dvdr * r_inv * wj_dr;
 
   /* Get the time derivative for h. */
   pi->h_dt -= mj * dvdr * r_inv / rhoj * wi_dr;
@@ -208,18 +205,15 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_force(
   const float P_over_rho_j = pressurej / (rhoj * rhoj) * pj->rho_dh;
 
   /* Compute dv dot r. */
-  float dvdr = (pi->v[0] - pj->v[0]) * dx[0] + (pi->v[1] - pj->v[1]) * dx[1] +
-               (pi->v[2] - pj->v[2]) * dx[2];
-  dvdr *= r_inv;
+  const float dvdr = (pi->v[0] - pj->v[0]) * dx[0] +
+                     (pi->v[1] - pj->v[1]) * dx[1] +
+                     (pi->v[2] - pj->v[2]) * dx[2];
 
-  /* Compute the relative velocity. (This is 0 if the particles move away from
-   * each other and negative otherwise) */
-  const float omega_ij = fminf(dvdr, 0.f);
 
   /* Compute sound speeds */
   const float ci = sqrtf(const_hydro_gamma * pressurei / rhoi);
   const float cj = sqrtf(const_hydro_gamma * pressurej / rhoj);
-  const float v_sig = ci + cj + 3.f * omega_ij;
+  const float v_sig = ci + cj;
 
   /* SPH acceleration term */
   const float sph_term = (P_over_rho_i * wi_dr + P_over_rho_j * wj_dr) * r_inv;
@@ -230,7 +224,7 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_force(
   pi->a_hydro[2] -= mj * sph_term * dx[2];
 
   /* Get the time derivative for u. */
-  pi->u_dt += P_over_rho_i * mj * dvdr * wi_dr;
+  pi->u_dt += P_over_rho_i * mj * dvdr * r_inv * wi_dr;
 
   /* Get the time derivative for h. */
   pi->h_dt -= mj * dvdr * r_inv / rhoj * wi_dr;