From 3348cd78f4e78e52d13f895d0f8b2ba7dfb95445 Mon Sep 17 00:00:00 2001
From: Matthieu Schaller <matthieu.schaller@durham.ac.uk>
Date: Tue, 22 Mar 2016 09:26:39 +0000
Subject: [PATCH] Save a sqrtf() call per particle in drift task
---
src/runner.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/src/runner.c b/src/runner.c
index 7eedb6adc7..92eb8c3df7 100644
--- a/src/runner.c
+++ b/src/runner.c
@@ -709,16 +709,18 @@ void runner_dodrift(struct runner *r, struct cell *c, int timer) {
/* Predict the values of the extra fields */
hydro_predict_extra(p, xp, ti_old, ti_current, timeBase);
- /* Compute motion since last cell construction */
- const float dx =
- sqrtf((p->x[0] - xp->x_old[0]) * (p->x[0] - xp->x_old[0]) +
- (p->x[1] - xp->x_old[1]) * (p->x[1] - xp->x_old[1]) +
- (p->x[2] - xp->x_old[2]) * (p->x[2] - xp->x_old[2]));
+ /* Compute (square of) motion since last cell construction */
+ const float dx = (p->x[0] - xp->x_old[0]) * (p->x[0] - xp->x_old[0]) +
+ (p->x[1] - xp->x_old[1]) * (p->x[1] - xp->x_old[1]) +
+ (p->x[2] - xp->x_old[2]) * (p->x[2] - xp->x_old[2]);
dx_max = fmaxf(dx_max, dx);
/* Maximal smoothing length */
h_max = fmaxf(p->h, h_max);
}
+
+ /* Now, get the maximal particle motion from its square */
+ dx_max = sqrtf(dx_max);
}
/* Otherwise, aggregate data from children. */
--
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