Merge branch 'corrected_drift_operation' into 'master'

Fix a drift integration mistake in the coupling of hydro and gravity

See merge request !1237

src/drift.h

@@ -151,9 +151,9 @@ __attribute__((always_inline)) INLINE static void drift_part(
 
   /* Predict velocities (for gravity terms) */
   if (p->gpart != NULL) {
-    p->v[0] += (p->gpart->a_grav[0] + p->gpart->a_grav_mesh[0]) * dt_kick_grav;
-    p->v[1] += (p->gpart->a_grav[1] + p->gpart->a_grav_mesh[1]) * dt_kick_grav;
-    p->v[2] += (p->gpart->a_grav[2] + p->gpart->a_grav_mesh[2]) * dt_kick_grav;
+    p->v[0] += xp->a_grav[0] * dt_kick_grav;
+    p->v[1] += xp->a_grav[1] * dt_kick_grav;
+    p->v[2] += xp->a_grav[2] * dt_kick_grav;
   }
 
   /* Predict the values of the extra fields */

src/hydro/AnarchyPU/hydro_part.h

@@ -55,6 +55,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Internal energy at the last full step. */
   float u_full;
 

src/hydro/Gadget2/hydro_part.h

@@ -54,6 +54,9 @@ struct xpart {
   /* Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /* Entropy at the last full step. */
   float entropy_full;
 

src/hydro/Gizmo/hydro_part.h

@@ -39,6 +39,9 @@ struct xpart {
   /* Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /* Additional data used to record cooling information */
   struct cooling_xpart_data cooling_data;
 

src/hydro/Minimal/hydro_part.h

@@ -58,6 +58,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Internal energy at the last full step. */
   float u_full;
 

src/hydro/Phantom/hydro_part.h

@@ -56,6 +56,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Internal energy at the last full step. */
   float u_full;
 

src/hydro/Planetary/hydro_part.h

@@ -61,6 +61,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Internal energy at the last full step. */
   float u_full;
 

src/hydro/PressureEnergy/hydro_part.h

@@ -58,6 +58,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Internal energy at the last full step. */
   float u_full;
 

src/hydro/PressureEnergyMorrisMonaghanAV/hydro_part.h

@@ -58,6 +58,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Internal energy at the last full step. */
   float u_full;
 

src/hydro/PressureEntropy/hydro_part.h

@@ -50,6 +50,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Entropy at the last full step. */
   float entropy_full;
 

src/hydro/SPHENIX/hydro_part.h

@@ -53,6 +53,9 @@ struct xpart {
   /*! Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /*! Internal energy at the last full step. */
   float u_full;
 

src/hydro/Shadowswift/hydro_part.h

@@ -41,6 +41,9 @@ struct xpart {
   /* Velocity at the last full step. */
   float v_full[3];
 
+  /*! Gravitational acceleration at the end of the last step */
+  float a_grav[3];
+
   /* Additional data used to record cooling information */
   struct cooling_xpart_data cooling_data;
 

src/runner_time_integration.c

@@ -177,6 +177,14 @@ void runner_do_kick1(struct runner *r, struct cell *c, const int timer) {
         kick_part(p, xp, dt_kick_hydro, dt_kick_grav, dt_kick_mesh_grav,
                   dt_kick_therm, dt_kick_corr, cosmo, hydro_props,
                   entropy_floor, ti_begin, ti_end, ti_begin_mesh, ti_end_mesh);
+
+        /* Update the accelerations to be used in the drift for hydro */
+        if (p->gpart != NULL) {
+
+          xp->a_grav[0] = p->gpart->a_grav[0] + p->gpart->a_grav_mesh[0];
+          xp->a_grav[1] = p->gpart->a_grav[1] + p->gpart->a_grav_mesh[1];
+          xp->a_grav[2] = p->gpart->a_grav[2] + p->gpart->a_grav_mesh[2];
+        }
       }
     }