Apply the same bug fix to the other hydro schemes.

src/hydro/Default/hydro.h

@@ -339,7 +339,7 @@ __attribute__((always_inline)) INLINE static void hydro_part_has_no_neighbours(
 
   /* Re-set problematic values */
   p->rho = p->mass * kernel_root * h_inv_dim;
-  p->density.wcount = kernel_root * kernel_norm * h_inv_dim;
+  p->density.wcount = kernel_root * h_inv_dim;
   p->rho_dh = 0.f;
   p->density.wcount_dh = 0.f;
   p->density.div_v = 0.f;
@@ -423,7 +423,7 @@ __attribute__((always_inline)) INLINE static void hydro_reset_acceleration(
   /* Reset the time derivatives. */
   p->force.u_dt = 0.0f;
   p->force.h_dt = 0.0f;
-  p->force.v_sig = 0.0f;
+  p->force.v_sig = p->force.soundspeed;
 }
 
 /**

src/hydro/Gadget2/hydro.h

@@ -349,7 +349,7 @@ __attribute__((always_inline)) INLINE static void hydro_part_has_no_neighbours(
 
   /* Re-set problematic values */
   p->rho = p->mass * kernel_root * h_inv_dim;
-  p->density.wcount = kernel_root * kernel_norm * h_inv_dim;
+  p->density.wcount = kernel_root * h_inv_dim;
   p->density.rho_dh = 0.f;
   p->density.wcount_dh = 0.f;
   p->density.div_v = 0.f;

src/hydro/GizmoMFM/hydro.h

@@ -398,7 +398,7 @@ __attribute__((always_inline)) INLINE static void hydro_part_has_no_neighbours(
   const float h_inv_dim = pow_dimension(h_inv); /* 1/h^d */
 
   /* Re-set problematic values */
-  p->density.wcount = kernel_root * kernel_norm * h_inv_dim;
+  p->density.wcount = kernel_root * h_inv_dim;
   p->density.wcount_dh = 0.f;
   p->geometry.volume = 1.0f;
   p->geometry.matrix_E[0][0] = 1.0f;

src/hydro/GizmoMFV/hydro.h

@@ -398,7 +398,7 @@ __attribute__((always_inline)) INLINE static void hydro_part_has_no_neighbours(
   const float h_inv_dim = pow_dimension(h_inv); /* 1/h^d */
 
   /* Re-set problematic values */
-  p->density.wcount = kernel_root * kernel_norm * h_inv_dim;
+  p->density.wcount = kernel_root * h_inv_dim;
   p->density.wcount_dh = 0.f;
   p->geometry.volume = 1.0f;
   p->geometry.matrix_E[0][0] = 1.0f;

src/hydro/PressureEnergy/hydro.h

@@ -403,7 +403,7 @@ __attribute__((always_inline)) INLINE static void hydro_part_has_no_neighbours(
   p->rho = p->mass * kernel_root * h_inv_dim;
   p->pressure_bar =
       p->mass * p->u * hydro_gamma_minus_one * kernel_root * h_inv_dim;
-  p->density.wcount = kernel_root * kernel_norm * h_inv_dim;
+  p->density.wcount = kernel_root * h_inv_dim;
   p->density.rho_dh = 0.f;
   p->density.wcount_dh = 0.f;
   p->density.pressure_bar_dh = 0.f;
@@ -480,7 +480,7 @@ __attribute__((always_inline)) INLINE static void hydro_reset_acceleration(
   /* Reset the time derivatives. */
   p->u_dt = 0.0f;
   p->force.h_dt = 0.0f;
-  p->force.v_sig = 0.0f;
+  p->force.v_sig = p->force.soundspeed;
 }
 
 /**

src/hydro/PressureEntropy/hydro.h

@@ -357,7 +357,7 @@ __attribute__((always_inline)) INLINE static void hydro_part_has_no_neighbours(
   /* Re-set problematic values */
   p->rho = p->mass * kernel_root * h_inv_dim;
   p->rho_bar = p->mass * kernel_root * h_inv_dim;
-  p->density.wcount = kernel_root * kernel_norm * h_inv_dim;
+  p->density.wcount = kernel_root * h_inv_dim;
   p->density.rho_dh = 0.f;
   p->density.wcount_dh = 0.f;
   p->density.pressure_dh = 0.f;
@@ -441,7 +441,7 @@ __attribute__((always_inline)) INLINE static void hydro_reset_acceleration(
   p->force.h_dt = 0.0f;
 
   /* Reset maximal signal velocity */
-  p->force.v_sig = 0.0f;
+  p->force.v_sig = p->force.soundspeed;
 }
 
 /**

src/hydro/Shadowswift/hydro.h

@@ -257,7 +257,7 @@ __attribute__((always_inline)) INLINE static void hydro_part_has_no_neighbours(
   const float h_inv_dim = pow_dimension(h_inv); /* 1/h^d */
 
   /* Re-set problematic values */
-  p->density.wcount = kernel_root * kernel_norm * h_inv_dim;
+  p->density.wcount = kernel_root * h_inv_dim;
   p->density.wcount_dh = 0.f;
 }