From e2afccea5e67b832bc66e3659992ab1a5b4a1d9e Mon Sep 17 00:00:00 2001
From: Pedro Gonnet <pedro.gonnet@durham.ac.uk>
Date: Fri, 22 Mar 2013 11:53:09 +0000
Subject: [PATCH] guess initial time step if dt_min is zero.
Former-commit-id: 67c1f9a70e35d07310a59e4c00b2ae08eef12952
---
src/engine.c | 19 +++++++++++++++----
src/engine.h | 5 ++++-
2 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/src/engine.c b/src/engine.c
index 5d23f431b9..5cf8986f2d 100644
--- a/src/engine.c
+++ b/src/engine.c
@@ -519,6 +519,8 @@ void engine_step ( struct engine *e , int sort_queues ) {
e->step += 1;
/* Does the time step need adjusting? */
+ if ( e->dt == 0 )
+ e->dt = e->dt_orig;
while ( dt_min < e->dt ) {
e->dt *= 0.5;
e->step *= 2;
@@ -529,6 +531,9 @@ void engine_step ( struct engine *e , int sort_queues ) {
e->step /= 2;
printf( "engine_step: dt_min is larger than twice the time step, adjusting to dt=%e.\n" , e->dt );
}
+
+ /* Set the system time. */
+ e->time = e->dt * e->step;
TIMER_TOC2(timer_step);
@@ -553,6 +558,7 @@ void engine_init ( struct engine *e , struct space *s , float dt , int nr_thread
cpu_set_t cpuset;
#endif
int k;
+ float dt_min = dt;
/* Store the values. */
e->s = s;
@@ -571,11 +577,16 @@ void engine_init ( struct engine *e , struct space *s , float dt , int nr_thread
e->barrier_count = 0;
/* Run through the parts and get the minimum time step. */
+ e->dt_orig = dt;
for ( k = 0 ; k < s->nr_parts ; k++ )
- if ( s->parts[k].dt > 0.0f )
- while ( s->parts[k].dt < dt )
- dt *= 0.5;
- e->dt_min = dt;
+ if ( s->parts[k].dt < dt_min )
+ dt_min = s->parts[k].dt;
+ if ( dt_min == 0.0f )
+ dt = 0.0f;
+ else
+ while ( dt > dt_min )
+ dt *= 0.5f;
+ e->dt = dt;
/* Allocate the queues. */
if ( posix_memalign( (void *)(&e->queues) , 64 , nr_queues * sizeof(struct queue) ) != 0 )
diff --git a/src/engine.h b/src/engine.h
index cb96b81510..12c3d9d814 100644
--- a/src/engine.h
+++ b/src/engine.h
@@ -57,11 +57,14 @@ struct engine {
float dt_min;
/* The system time step. */
- float dt;
+ float dt, dt_orig;
/* The current step number. */
int step;
+ /* The current system time. */
+ float time;
+
/* Data for the threads' barrier. */
pthread_mutex_t barrier_mutex;
pthread_cond_t barrier_cond;
--
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