Moved the 'kick' operation to a separate file for clarity.

src/Makefile.am

@@ -47,7 +47,7 @@ AM_SOURCES = space.c runner.c queue.c task.c cell.c engine.c \
 
 # Include files for distribution, not installation.
 nobase_noinst_HEADERS = approx_math.h atomic.h cycle.h error.h inline.h kernel_hydro.h kernel_gravity.h \
-		 vector.h runner_doiact.h runner_doiact_grav.h units.h intrinsics.h minmax.h \
+		 vector.h runner_doiact.h runner_doiact_grav.h units.h intrinsics.h minmax.h kick.h \
 		 gravity.h gravity_io.h \
 		 gravity/Default/gravity.h gravity/Default/gravity_iact.h gravity/Default/gravity_io.h \
 		 gravity/Default/gravity_debug.h gravity/Default/gravity_part.h  \

src/kick.h

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2016 Matthieu Schaller (matthieu.schaller@durham.ac.uk)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#ifndef SWIFT_KICK_H
+#define SWIFT_KICK_H
+
+/* Config parameters. */
+#include "../config.h"
+
+/**
+ * @brief Perform the 'kick' operation on a #gpart
+ *
+ * @param gp The #gpart to kick.
+ * @param new_dti The (integer) time-step for this kick.
+ * @param timeBase The minimal allowed time-step size.
+ */
+__attribute__((always_inline)) INLINE static void kick_gpart(struct gpart* gp,
+                                                             int new_dti,
+                                                             double timeBase) {
+
+  /* Compute the time step for this kick */
+  const int ti_start = (gp->ti_begin + gp->ti_end) / 2;
+  const int ti_end = gp->ti_end + new_dti / 2;
+  const double dt = (ti_end - ti_start) * timeBase;
+  const double half_dt = (ti_end - gp->ti_end) * timeBase;
+
+  /* Move particle forward in time */
+  gp->ti_begin = gp->ti_end;
+  gp->ti_end = gp->ti_begin + new_dti;
+
+  /* Kick particles in momentum space */
+  gp->v_full[0] += gp->a_grav[0] * dt;
+  gp->v_full[1] += gp->a_grav[1] * dt;
+  gp->v_full[2] += gp->a_grav[2] * dt;
+
+  /* Extra kick work */
+  gravity_kick_extra(gp, dt, half_dt);
+}
+
+/**
+ * @brief Perform the 'kick' operation on a #part
+ *
+ * @param p The #part to kick.
+ * @param xp The #xpart of the particle.
+ * @param new_dti The (integer) time-step for this kick.
+ * @param timeBase The minimal allowed time-step size.
+ */
+__attribute__((always_inline)) INLINE static void kick_part(struct part* p,
+                                                            struct xpart* xp,
+                                                            int new_dti,
+                                                            double timeBase) {
+
+  /* Compute the time step for this kick */
+  const int ti_start = (p->ti_begin + p->ti_end) / 2;
+  const int ti_end = p->ti_end + new_dti / 2;
+  const double dt = (ti_end - ti_start) * timeBase;
+  const double half_dt = (ti_end - p->ti_end) * timeBase;
+
+  /* Move particle forward in time */
+  p->ti_begin = p->ti_end;
+  p->ti_end = p->ti_begin + new_dti;
+  if (p->gpart != NULL) {
+    p->gpart->ti_begin = p->ti_begin;
+    p->gpart->ti_end = p->ti_end;
+  }
+
+  /* Get the acceleration */
+  float a_tot[3] = {p->a_hydro[0], p->a_hydro[1], p->a_hydro[2]};
+  if (p->gpart != NULL) {
+    a_tot[0] += p->gpart->a_grav[0];
+    a_tot[1] += p->gpart->a_grav[1];
+    a_tot[1] += p->gpart->a_grav[2];
+  }
+
+  /* Kick particles in momentum space */
+  xp->v_full[0] += a_tot[0] * dt;
+  xp->v_full[1] += a_tot[1] * dt;
+  xp->v_full[2] += a_tot[2] * dt;
+  if (p->gpart != NULL) {
+    p->gpart->v_full[0] = xp->v_full[0];
+    p->gpart->v_full[1] = xp->v_full[1];
+    p->gpart->v_full[2] = xp->v_full[2];
+  }
+
+  /* Go back by half-step for the hydro velocity */
+  p->v[0] = xp->v_full[0] - half_dt * a_tot[0];
+  p->v[1] = xp->v_full[1] - half_dt * a_tot[1];
+  p->v[2] = xp->v_full[2] - half_dt * a_tot[2];
+
+  /* Extra kick work */
+  hydro_kick_extra(p, xp, dt, half_dt);
+  if (p->gpart != NULL) gravity_kick_extra(p->gpart, dt, half_dt);
+}
+
+#endif /* SWIFT_KICK_H */

src/runner.c

@@ -47,6 +47,7 @@
 #include "gravity.h"
 #include "hydro_properties.h"
 #include "hydro.h"
+#include "kick.h"
 #include "minmax.h"
 #include "scheduler.h"
 #include "space.h"
@@ -941,35 +942,20 @@ void runner_do_kick_fixdt(struct runner *r, struct cell *c, int timer) {
   /* No children? */
   if (!c->split) {
 
-    /* Loop over the g-particles and kick the active ones. */
+    /* Loop over the g-particles and kick everyone. */
     for (int k = 0; k < gcount; k++) {
 
       /* Get a handle on the part. */
       struct gpart *const gp = &gparts[k];
 
-      /* If the g-particle has no counterpart and needs to be kicked */
+      /* If the g-particle has no counterpart */
       if (gp->id < 0) {
 
         /* First, finish the force calculation */
         gravity_end_force(gp);
 
-        /* Compute the time step for this kick */
-        const int ti_start = (gp->ti_begin + gp->ti_end) / 2;
-        const int ti_end = gp->ti_end + new_dti / 2;
-        const double dt = (ti_end - ti_start) * timeBase;
-        const double half_dt = (ti_end - gp->ti_end) * timeBase;
-
-        /* Move particle forward in time */
-        gp->ti_begin = gp->ti_end;
-        gp->ti_end = gp->ti_begin + new_dti;
-
-        /* Kick particles in momentum space */
-        gp->v_full[0] += gp->a_grav[0] * dt;
-        gp->v_full[1] += gp->a_grav[1] * dt;
-        gp->v_full[2] += gp->a_grav[2] * dt;
-
-        /* Extra kick work */
-        gravity_kick_extra(gp, dt, half_dt);
+        /* Kick the g-particle forward */
+        kick_gpart(gp, new_dti, timeBase);
 
         /* Number of updated g-particles */
         g_updated++;
@@ -982,7 +968,7 @@ void runner_do_kick_fixdt(struct runner *r, struct cell *c, int timer) {
 
     /* Now do the hydro ones... */
 
-    /* Loop over the particles and kick the active ones. */
+    /* Loop over the particles and kick everyone. */
     for (int k = 0; k < count; k++) {
 
       /* Get a handle on the part. */
@@ -996,47 +982,8 @@ void runner_do_kick_fixdt(struct runner *r, struct cell *c, int timer) {
       hydro_end_force(p);
       if (p->gpart != NULL) gravity_end_force(p->gpart);
 
-      /* Compute the time step for this kick */
-      const int ti_start = (p->ti_begin + p->ti_end) / 2;
-      const int ti_end = p->ti_end + new_dti / 2;
-      const double dt = (ti_end - ti_start) * timeBase;
-      const double half_dt = (ti_end - p->ti_end) * timeBase;
-
-      /* Move particle forward in time */
-      p->ti_begin = p->ti_end;
-      p->ti_end = p->ti_begin + new_dti;
-      if (p->gpart != NULL) {
-        p->gpart->ti_begin = p->ti_begin;
-        p->gpart->ti_end = p->ti_end;
-      }
-
-      /* Get the acceleration */
-      float a_tot[3] = {p->a_hydro[0], p->a_hydro[1], p->a_hydro[2]};
-      if (p->gpart != NULL) {
-        a_tot[0] += p->gpart->a_grav[0];
-        a_tot[1] += p->gpart->a_grav[1];
-        a_tot[1] += p->gpart->a_grav[2];
-      }
-
-      /* Kick particles in momentum space */
-      xp->v_full[0] += a_tot[0] * dt;
-      xp->v_full[1] += a_tot[1] * dt;
-      xp->v_full[2] += a_tot[2] * dt;
-
-      if (p->gpart != NULL) {
-        p->gpart->v_full[0] = xp->v_full[0];
-        p->gpart->v_full[1] = xp->v_full[1];
-        p->gpart->v_full[2] = xp->v_full[2];
-      }
-
-      /* Go back by half-step for the hydro velocity */
-      p->v[0] = xp->v_full[0] - half_dt * a_tot[0];
-      p->v[1] = xp->v_full[1] - half_dt * a_tot[1];
-      p->v[2] = xp->v_full[2] - half_dt * a_tot[2];
-
-      /* Extra kick work */
-      hydro_kick_extra(p, xp, dt, half_dt);
-      if (p->gpart != NULL) gravity_kick_extra(p->gpart, dt, half_dt);
+      /* Kick the particle forward */
+      kick_part(p, xp, new_dti, timeBase);
 
       /* Number of updated particles */
       updated++;
@@ -1209,24 +1156,7 @@ void runner_do_kick(struct runner *r, struct cell *c, int timer) {
           }
 
           /* Now we have a time step, proceed with the kick */
-
-          /* Compute the time step for this kick */
-          const int ti_start = (gp->ti_begin + gp->ti_end) / 2;
-          const int ti_end = gp->ti_end + new_dti / 2;
-          const double dt = (ti_end - ti_start) * timeBase;
-          const double half_dt = (ti_end - gp->ti_end) * timeBase;
-
-          /* Move particle forward in time */
-          gp->ti_begin = gp->ti_end;
-          gp->ti_end = gp->ti_begin + new_dti;
-
-          /* Kick particles in momentum space */
-          gp->v_full[0] += gp->a_grav[0] * dt;
-          gp->v_full[1] += gp->a_grav[1] * dt;
-          gp->v_full[2] += gp->a_grav[2] * dt;
-
-          /* Extra kick work */
-          gravity_kick_extra(gp, dt, half_dt);
+          kick_gpart(gp, new_dti, timeBase);
 
           /* Number of updated g-particles */
           g_updated++;
@@ -1309,48 +1239,7 @@ void runner_do_kick(struct runner *r, struct cell *c, int timer) {
         }
 
         /* Now we have a time step, proceed with the kick */
-
-        /* Compute the time step for this kick */
-        const int ti_start = (p->ti_begin + p->ti_end) / 2;
-        const int ti_end = p->ti_end + new_dti / 2;
-        const double dt = (ti_end - ti_start) * timeBase;
-        const double half_dt = (ti_end - p->ti_end) * timeBase;
-
-        /* Move particle forward in time */
-        p->ti_begin = p->ti_end;
-        p->ti_end = p->ti_begin + new_dti;
-        if (p->gpart != NULL) {
-          p->gpart->ti_begin = p->ti_begin;
-          p->gpart->ti_end = p->ti_end;
-        }
-
-        /* Get the acceleration */
-        float a_tot[3] = {p->a_hydro[0], p->a_hydro[1], p->a_hydro[2]};
-        if (p->gpart != NULL) {
-          a_tot[0] += p->gpart->a_grav[0];
-          a_tot[1] += p->gpart->a_grav[1];
-          a_tot[1] += p->gpart->a_grav[2];
-        }
-
-        /* Kick particles in momentum space */
-        xp->v_full[0] += a_tot[0] * dt;
-        xp->v_full[1] += a_tot[1] * dt;
-        xp->v_full[2] += a_tot[2] * dt;
-
-        if (p->gpart != NULL) {
-          p->gpart->v_full[0] = xp->v_full[0];
-          p->gpart->v_full[1] = xp->v_full[1];
-          p->gpart->v_full[2] = xp->v_full[2];
-        }
-
-        /* Go back by half-step for the hydro velocity */
-        p->v[0] = xp->v_full[0] - half_dt * a_tot[0];
-        p->v[1] = xp->v_full[1] - half_dt * a_tot[1];
-        p->v[2] = xp->v_full[2] - half_dt * a_tot[2];
-
-        /* Extra kick work */
-        hydro_kick_extra(p, xp, dt, half_dt);
-        if (p->gpart != NULL) gravity_kick_extra(p->gpart, dt, half_dt);
+        kick_part(p, xp, new_dti, timeBase);
 
         /* Number of updated particles */
         updated++;