Enforce periodicity

sample/gadgetToArray.cpp

@@ -75,6 +75,11 @@ int main(int argc, char **argv)
           parts[q][0] = p->Pos[0][i]/1000;
           parts[q][1] = p->Pos[1][i]/1000;
           parts[q][2] = p->Pos[2][i]/1000;
+          for (int j = 0; j < 3; j++)
+            {
+              while (parts[q][j] < 0) parts[q][j] += L0;
+              while (parts[q][j] >= L0) parts[q][j] -= L0;
+            }
           parts[q][3] = p->Vel[0][i];
           parts[q][4] = p->Vel[1][i];
           parts[q][5] = p->Vel[2][i];