diff --git a/src/Makefile.am b/src/Makefile.am
index e95a00125e3c86ec32d3ae632065fd1d071877ac..7c510004d9ab3f82b6490f3bf896fb75f941b409 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -77,8 +77,31 @@ nobase_noinst_HEADERS = align.h approx_math.h atomic.h cycle.h error.h inline.h
                  hydro/Gadget2/hydro_debug.h hydro/Gadget2/hydro_part.h \
 		 hydro/PressureEntropy/hydro.h hydro/PressureEntropy/hydro_iact.h hydro/PressureEntropy/hydro_io.h \
                  hydro/PressureEntropy/hydro_debug.h hydro/PressureEntropy/hydro_part.h \
-		 hydro/Gizmo/hydro.h hydro/Gizmo/hydro_iact.h hydro/Gizmo/hydro_io.h \
-                 hydro/Gizmo/hydro_debug.h hydro/Gizmo/hydro_part.h \
+		 hydro/Gizmo/hydro.h hydro/Gizmo/hydro_iact.h \
+                 hydro/Gizmo/hydro_io.h hydro/Gizmo/hydro_debug.h \
+                 hydro/Gizmo/hydro_part.h \
+                 hydro/Gizmo/hydro_gradients_gizmo.h \
+                 hydro/Gizmo/hydro_gradients.h \
+                 hydro/Gizmo/hydro_gradients_sph.h \
+                 hydro/Gizmo/hydro_slope_limiters_cell.h \
+                 hydro/Gizmo/hydro_slope_limiters_face.h \
+                 hydro/Gizmo/hydro_slope_limiters.h \
+                 hydro/Shadowswift/hydro_debug.h \
+                 hydro/Shadowswift/hydro_gradients.h hydro/Shadowswift/hydro.h \
+                 hydro/Shadowswift/hydro_iact.h \
+                 hydro/Shadowswift/hydro_io.h \
+                 hydro/Shadowswift/hydro_part.h \
+                 hydro/Shadowswift/hydro_slope_limiters_cell.h \
+                 hydro/Shadowswift/hydro_slope_limiters_face.h \
+                 hydro/Shadowswift/hydro_slope_limiters.h \
+                 hydro/Shadowswift/voronoi1d_algorithm.h \
+                 hydro/Shadowswift/voronoi1d_cell.h \
+                 hydro/Shadowswift/voronoi2d_algorithm.h \
+                 hydro/Shadowswift/voronoi2d_cell.h \
+                 hydro/Shadowswift/voronoi3d_algorithm.h \
+                 hydro/Shadowswift/voronoi3d_cell.h \
+                 hydro/Shadowswift/voronoi_algorithm.h \
+                 hydro/Shadowswift/voronoi_cell.h \
 	         riemann/riemann_hllc.h riemann/riemann_trrs.h \
 		 riemann/riemann_exact.h riemann/riemann_vacuum.h \
 	 	 stars.h stars_io.h \
diff --git a/src/hydro/Shadowswift/voronoi2d_algorithm.h b/src/hydro/Shadowswift/voronoi2d_algorithm.h
index ad4d565fbf817da7b7116a0c619a93b5aee1917c..947595107a4d3705c52c982da0dc8e54a5c2376e 100644
--- a/src/hydro/Shadowswift/voronoi2d_algorithm.h
+++ b/src/hydro/Shadowswift/voronoi2d_algorithm.h
@@ -43,6 +43,8 @@
 #define VORONOI2D_BOX_TOP 18446744073709551604llu
 #define VORONOI2D_BOX_BOTTOM 18446744073709551605llu
 
+#define VORONOI2D_TOLERANCE 1.e-6f
+
 /**
  * @brief Initialize a 2D Voronoi cell.
  *
@@ -152,7 +154,7 @@ __attribute__((always_inline)) INLINE void voronoi_cell_interact(
   /* start testing a random vertex: the first one */
   test = cell->vertices[0][0] * half_dx[0] + cell->vertices[0][1] * half_dx[1] -
          r2;
-  if (test < 0.) {
+  if (test < -VORONOI2D_TOLERANCE) {
 /* vertex is below midline */
 #ifdef VORONOI_VERBOSE
     message("First vertex is below midline (%g %g --> %g)!",
@@ -215,7 +217,7 @@ __attribute__((always_inline)) INLINE void voronoi_cell_interact(
     i = 1;
     test = cell->vertices[i][0] * half_dx[0] +
            cell->vertices[i][1] * half_dx[1] - r2;
-    while (i < cell->nvert && test >= 0.) {
+    while (i < cell->nvert && test > -VORONOI2D_TOLERANCE) {
       /* make sure we always store the most recent test result */
       a1 = test;
       ++i;
@@ -272,7 +274,7 @@ __attribute__((always_inline)) INLINE void voronoi_cell_interact(
          r2;
   /* this loop can never deadlock, as we know there is at least 1 vertex below
      the midline */
-  while (test >= 0.) {
+  while (test > -VORONOI2D_TOLERANCE) {
     /* make sure we always store the most recent test result */
     a2 = test;
     i += increment;
diff --git a/src/riemann/riemann_exact.h b/src/riemann/riemann_exact.h
index 4a20561def8ac56889d4e2d836dd698e663e8d7e..4a7b40ae78c4c3f1a880539367172894fe298995 100644
--- a/src/riemann/riemann_exact.h
+++ b/src/riemann/riemann_exact.h
@@ -206,7 +206,6 @@ __attribute__((always_inline)) INLINE static float riemann_solve_brent(
   float fa, fb, fc, fs;
   float tmp, tmp2;
   int mflag;
-  int i;
 
   a = lower_limit;
   b = upper_limit;
@@ -243,7 +242,6 @@ __attribute__((always_inline)) INLINE static float riemann_solve_brent(
   c = a;
   fc = fa;
   mflag = 1;
-  i = 0;
 
   while (!(fb == 0.0f) && (fabs(a - b) > error_tol * 0.5f * (a + b))) {
     if ((fa != fc) && (fb != fc)) /* Inverse quadratic interpolation */
@@ -286,7 +284,6 @@ __attribute__((always_inline)) INLINE static float riemann_solve_brent(
       fa = fb;
       fb = tmp;
     }
-    i++;
   }
   return b;
 }
diff --git a/tests/testVoronoi2D.c b/tests/testVoronoi2D.c
index 8e2c875ee1b41828a0b39aa896f02dff0ccbac88..7a35961952079494b0d1567db57abd29fa1df35b 100644
--- a/tests/testVoronoi2D.c
+++ b/tests/testVoronoi2D.c
@@ -197,12 +197,11 @@ int main() {
     /* Check the neighbour relations for an arbitrary cell: cell 44
        We plotted the grid and manually found the correct neighbours and their
        order. */
-    assert(cells[44].nvert == 5);
+    assert(cells[44].nvert == 4);
     assert(cells[44].ngbs[0] == 34);
-    assert(cells[44].ngbs[1] == 35);
-    assert(cells[44].ngbs[2] == 45);
-    assert(cells[44].ngbs[3] == 54);
-    assert(cells[44].ngbs[4] == 43);
+    assert(cells[44].ngbs[1] == 45);
+    assert(cells[44].ngbs[2] == 54);
+    assert(cells[44].ngbs[3] == 43);
 
     message("Done.");
   }