Apply long-range gravity correction only when running with periodic BCs on.

src/gravity/Default/gravity_iact.h

@@ -32,7 +32,7 @@
  */
 __attribute__((always_inline)) INLINE static void runner_iact_grav_pp(
     float rlr_inv, float r2, const float *dx, struct gpart *gpi,
-    struct gpart *gpj) {
+    struct gpart *gpj, int periodic) {
 
   /* Apply the gravitational acceleration. */
   const float r = sqrtf(r2);
@@ -49,7 +49,10 @@ __attribute__((always_inline)) INLINE static void runner_iact_grav_pp(
 #endif
 
   /* Get long-range correction */
-  kernel_long_grav_eval(u, &f_lr);
+  if (periodic)
+    kernel_long_grav_eval(u, &f_lr);
+  else
+    f_lr = 1.f;
 
   if (r >= hi) {
 
@@ -101,7 +104,7 @@ __attribute__((always_inline)) INLINE static void runner_iact_grav_pp(
  */
 __attribute__((always_inline)) INLINE static void runner_iact_grav_pp_nonsym(
     float rlr_inv, float r2, const float *dx, struct gpart *gpi,
-    const struct gpart *gpj) {
+    const struct gpart *gpj, int periodic) {
 
   /* Apply the gravitational acceleration. */
   const float r = sqrtf(r2);
@@ -116,7 +119,10 @@ __attribute__((always_inline)) INLINE static void runner_iact_grav_pp_nonsym(
 #endif
 
   /* Get long-range correction */
-  kernel_long_grav_eval(u, &f_lr);
+  if (periodic)
+    kernel_long_grav_eval(u, &f_lr);
+  else
+    f_lr = 1.f;
 
   if (r >= hi) {
 

src/runner_doiact_grav.h

@@ -267,7 +267,7 @@ void runner_dopair_grav_pp(struct runner *r, struct cell *ci, struct cell *cj) {
 #endif
 
         /* Interact ! */
-        runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpi, gpj);
+        runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpi, gpj, periodic);
 
 #ifdef SWIFT_DEBUG_CHECKS
         gpi->num_interacted++;
@@ -310,7 +310,7 @@ void runner_dopair_grav_pp(struct runner *r, struct cell *ci, struct cell *cj) {
 #endif
 
         /* Interact ! */
-        runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpj, gpi);
+        runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpj, gpi, periodic);
 
 #ifdef SWIFT_DEBUG_CHECKS
         gpj->num_interacted++;
@@ -334,6 +334,8 @@ void runner_doself_grav_pp(struct runner *r, struct cell *c) {
 
   /* Some constants */
   const struct engine *e = r->e;
+  const struct space *s = e->s;
+  const int periodic = s->periodic;
   const float a_smooth = e->gravity_properties->a_smooth;
   const float rlr_inv = 1. / (a_smooth * c->super->width[0]);
 
@@ -397,7 +399,7 @@ void runner_doself_grav_pp(struct runner *r, struct cell *c) {
       /* Interact ! */
       if (gpart_is_active(gpi, e) && gpart_is_active(gpj, e)) {
 
-        runner_iact_grav_pp(rlr_inv, r2, dx, gpi, gpj);
+        runner_iact_grav_pp(rlr_inv, r2, dx, gpi, gpj, periodic);
 
 #ifdef SWIFT_DEBUG_CHECKS
         gpi->num_interacted++;
@@ -408,7 +410,7 @@ void runner_doself_grav_pp(struct runner *r, struct cell *c) {
 
         if (gpart_is_active(gpi, e)) {
 
-          runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpi, gpj);
+          runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpi, gpj, periodic);
 
 #ifdef SWIFT_DEBUG_CHECKS
           gpi->num_interacted++;
@@ -419,7 +421,7 @@ void runner_doself_grav_pp(struct runner *r, struct cell *c) {
           dx[0] = -dx[0];
           dx[1] = -dx[1];
           dx[2] = -dx[2];
-          runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpj, gpi);
+          runner_iact_grav_pp_nonsym(rlr_inv, r2, dx, gpj, gpi, periodic);
 
 #ifdef SWIFT_DEBUG_CHECKS
           gpj->num_interacted++;

src/tools.c

@@ -430,7 +430,7 @@ void pairs_single_grav(double *dim, long long int pid,
       fdx[i] = dx[i];
     }
     r2 = fdx[0] * fdx[0] + fdx[1] * fdx[1] + fdx[2] * fdx[2];
-    runner_iact_grav_pp(0.f, r2, fdx, &pi, &pj);
+    runner_iact_grav_pp(0.f, r2, fdx, &pi, &pj, 0);
     a[0] += pi.a_grav[0];
     a[1] += pi.a_grav[1];
     a[2] += pi.a_grav[2];
@@ -790,7 +790,7 @@ void gravity_n2(struct gpart *gparts, const int gcount,
       if (r2 < max_d2 || 1) {
 
         /* Apply the gravitational acceleration. */
-        runner_iact_grav_pp(rlr_inv, r2, dx, gpi, gpj);
+        runner_iact_grav_pp(rlr_inv, r2, dx, gpi, gpj, 0);
       }
     }
   }