Default SPH also moved to integer timeline

src/hydro/Default/hydro.h

@@ -17,6 +17,8 @@
  *
  ******************************************************************************/
 
+#include "approx_math.h"
+
 /**
  * @brief Computes the hydro time-step of a given particle
  *
@@ -108,7 +110,7 @@ __attribute__((always_inline))
  * @param time The current time
  */
 __attribute__((always_inline)) INLINE static void hydro_prepare_force(
-    struct part* p, struct xpart* xp, float time) {
+    struct part* p, struct xpart* xp, int ti_current, double timeBase) {
 
   /* Some smoothing length multiples. */
   const float h = p->h;
@@ -146,7 +148,7 @@ __attribute__((always_inline)) INLINE static void hydro_prepare_force(
                           (const_viscosity_alpha_max - p->alpha) * S;
 
   /* Update particle's viscosity paramter */
-  p->alpha += alpha_dot * (p->t_end - p->t_begin);
+  p->alpha += alpha_dot * (p->ti_end - p->ti_begin) * timeBase;
 }
 
 /**
@@ -178,18 +180,18 @@ __attribute__((always_inline))
  * @param xp The extended data of the particle
  * @param t0 The time at the start of the drift
  * @param t1 The time at the end of the drift
+ * @param timeBase The minimal time-step size
  */
 __attribute__((always_inline)) INLINE static void hydro_predict_extra(
-    struct part* p, struct xpart* xp, float t0, float t1) {
+    struct part* p, struct xpart* xp, int t0, int t1, double timeBase) {
   float u, w;
 
-  const float dt = t1 - t0;
+  const float dt = (t1 - t0) * timeBase;
 
   /* Predict internal energy */
   w = p->force.u_dt / p->u * dt;
-  if (fabsf(w) < 0.01f) /* 1st order expansion of exp(w) */
-    u = p->u *=
-        1.0f + w * (1.0f + w * (0.5f + w * (1.0f / 6.0f + 1.0f / 24.0f * w)));
+  if (fabsf(w) < 0.2f)
+    u = p->u *= approx_expf(w);
   else
     u = p->u *= expf(w);
 
@@ -216,7 +218,7 @@ __attribute__((always_inline))
  * @param half_dt The half time-step for this kick
  */
 __attribute__((always_inline)) INLINE static void hydro_kick_extra(
-    struct part* p, struct xpart* xp, float dt, float half_dt) { }
+    struct part* p, struct xpart* xp, float dt, float half_dt) {}
 
 /**
  * @brief Converts hydro quantity of a particle

src/hydro/Default/hydro_debug.h

@@ -23,9 +23,9 @@ __attribute__((always_inline))
       "x=[%.3e,%.3e,%.3e], "
       "v=[%.3e,%.3e,%.3e],v_full=[%.3e,%.3e,%.3e] \n a=[%.3e,%.3e,%.3e],\n "
       "h=%.3e, "
-      "wcount=%d, m=%.3e, dh_drho=%.3e, rho=%.3e, t_begin=%.3e, t_end=%.3e\n",
+      "wcount=%d, m=%.3e, dh_drho=%.3e, rho=%.3e, t_begin=%d, t_end=%d\n",
       p->x[0], p->x[1], p->x[2], p->v[0], p->v[1], p->v[2], xp->v_full[0],
       xp->v_full[1], xp->v_full[2], p->a_hydro[0], p->a_hydro[1], p->a_hydro[2],
-      p->h, (int)p->density.wcount, p->mass, p->rho_dh, p->rho, p->t_begin,
-      p->t_end);
+      p->h, (int)p->density.wcount, p->mass, p->rho_dh, p->rho, p->ti_begin,
+      p->ti_end);
 }

src/hydro/Default/hydro_part.h

@@ -50,10 +50,10 @@ struct part {
   float h_dt;
 
   /* Particle time of beginning of time-step. */
-  float t_begin;
+  int ti_begin;
 
   /* Particle time of end of time-step. */
-  float t_end;
+  int ti_end;
 
   /* Particle internal energy. */
   float u;

src/hydro/Gadget2/hydro.h

@@ -81,10 +81,10 @@ __attribute__((always_inline))
  * and add the self-contribution term.
  *
  * @param p The particle to act upon
- * @param time The current time
+ * @param ti_current The current time (on the integer timeline)
  */
 __attribute__((always_inline))
-    INLINE static void hydro_end_density(struct part* p, float time) {
+    INLINE static void hydro_end_density(struct part* p, int ti_current) {
 
   /* Some smoothing length multiples. */
   const float h = p->h;

src/runner.c

@@ -583,7 +583,7 @@ void runner_doghost(struct runner *r, struct cell *c) {
       if (p->ti_end <= ti_current) {
 
         /* Finish the density calculation */
-        hydro_end_density(p, ti_current);  // MATTHIEU
+        hydro_end_density(p, ti_current);
 
         /* If no derivative, double the smoothing length. */
         if (p->density.wcount_dh == 0.0f) h_corr = p->h;
@@ -800,7 +800,6 @@ void runner_dodrift(struct runner *r, struct cell *c, int timer) {
 
 void runner_dokick(struct runner *r, struct cell *c, int timer) {
 
-  // const float dt_max_timeline = r->e->timeEnd - r->e->timeBegin;
   const float global_dt_min = r->e->dt_min;
   const float global_dt_max = r->e->dt_max;
   const float ti_current = r->e->ti_current;