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authorGravatar Robert C. Helling <helling@atdotde.de>2017-08-24 23:45:33 +0200
committerGravatar Dirk Hohndel <dirk@hohndel.org>2017-08-29 06:49:44 -0700
commit33fa336be6df27ff757516c917583ece17e62862 (patch)
treeebea6a4562fe4bb67c595c9d4a9ddcd089a867af /core
parent82aac4efff7e0836e879e52b4e4e0f7301b165a9 (diff)
downloadsubsurface-33fa336be6df27ff757516c917583ece17e62862.tar.gz
Find deco stop time by binary search instead of iteration
This allows to go to much smaller granularity without severe performance penalty. It should also increase performance for long decompression times. Currently this leads to missing cached tissue factors, the caching has to be adopted to this. Also, for the time being this breaks the bottom gas breaks feature. Signed-off-by: Robert C. Helling <helling@atdotde.de>
Diffstat (limited to 'core')
-rw-r--r--core/planner.c67
1 files changed, 45 insertions, 22 deletions
diff --git a/core/planner.c b/core/planner.c
index 553e152fa..65bd5b488 100644
--- a/core/planner.c
+++ b/core/planner.c
@@ -558,7 +558,7 @@ void track_ascent_gas(int depth, cylinder_t *cylinder, int avg_depth, int bottom
}
// Determine whether ascending to the next stop will break the ceiling. Return true if the ascent is ok, false if it isn't.
-bool trial_ascent(int trial_depth, int stoplevel, int avg_depth, int bottom_time, struct gasmix *gasmix, int po2, double surface_pressure)
+bool trial_ascent(int wait_time, int trial_depth, int stoplevel, int avg_depth, int bottom_time, struct gasmix *gasmix, int po2, double surface_pressure, struct dive *dive)
{
bool clear_to_ascend = true;
@@ -568,9 +568,13 @@ bool trial_ascent(int trial_depth, int stoplevel, int avg_depth, int bottom_time
// deeper than the next stop (thus the offgasing during the ascent is ignored).
// However, we still need to make sure we don't break the ceiling due to on-gassing during ascent.
cache_deco_state(&trial_cache);
- if (decoMode() == VPMB && (deco_allowed_depth(tissue_tolerance_calc(&displayed_dive,
- depth_to_bar(stoplevel, &displayed_dive)),
- surface_pressure, &displayed_dive, 1) > stoplevel)) {
+ if (wait_time)
+ add_segment(depth_to_bar(trial_depth, dive),
+ gasmix,
+ wait_time, po2, dive, prefs.decosac);
+ if (decoMode() == VPMB && (deco_allowed_depth(tissue_tolerance_calc(dive,
+ depth_to_bar(stoplevel, dive)),
+ surface_pressure, dive, 1) > stoplevel)) {
restore_deco_state(trial_cache, false);
free(trial_cache);
return false;
@@ -580,11 +584,11 @@ bool trial_ascent(int trial_depth, int stoplevel, int avg_depth, int bottom_time
int deltad = ascent_velocity(trial_depth, avg_depth, bottom_time) * TIMESTEP;
if (deltad > trial_depth) /* don't test against depth above surface */
deltad = trial_depth;
- add_segment(depth_to_bar(trial_depth, &displayed_dive),
+ add_segment(depth_to_bar(trial_depth, dive),
gasmix,
- TIMESTEP, po2, &displayed_dive, prefs.decosac);
- if (deco_allowed_depth(tissue_tolerance_calc(&displayed_dive, depth_to_bar(trial_depth, &displayed_dive)),
- surface_pressure, &displayed_dive, 1) > trial_depth - deltad) {
+ TIMESTEP, po2, dive, prefs.decosac);
+ if (deco_allowed_depth(tissue_tolerance_calc(dive, depth_to_bar(trial_depth, dive)),
+ surface_pressure, dive, 1) > trial_depth - deltad) {
/* We should have stopped */
clear_to_ascend = false;
break;
@@ -613,6 +617,27 @@ bool enough_gas(int current_cylinder)
return true;
}
+/* Do a binary search for the time the ceiling is clear to ascent to target_depth.
+ * Minimal solution is min + 1, and the solution should be an integer multiple of stepsize.
+ * leap is a guess for the maximum but there is no guarantee that leap is an upper limit.
+ * So we always test at the upper bundary, not in the middle!
+ */
+
+int wait_until(struct dive *dive, int clock, int min, int leap, int stepsize, int depth, int target_depth, int avg_depth, int bottom_time, struct gasmix *gasmix, int po2, double surface_pressure)
+{
+ // Round min + leap up to the next multiple of stepsize
+ int upper = min + leap + stepsize - 1 - (min + leap - 1) % stepsize;
+ printf("clock: %d min: %d leap: %d, depth %d\n", clock / 60, min / 60, leap, depth);
+ // Is the upper boundary too small?
+ if (!trial_ascent(upper - clock, depth, target_depth, avg_depth, bottom_time, gasmix, po2, surface_pressure, dive))
+ return wait_until(dive, clock, upper, leap, stepsize, depth, target_depth, avg_depth, bottom_time, gasmix, po2, surface_pressure);
+
+ if (upper - min <= stepsize)
+ return upper;
+
+ return wait_until(dive, clock, min, leap / 2, stepsize, depth, target_depth, avg_depth, bottom_time, gasmix, po2, surface_pressure);
+}
+
// Work out the stops. Return value is if there were any mandatory stops.
bool plan(struct diveplan *diveplan, struct dive *dive, int timestep, struct deco_state **cached_datap, bool is_planner, bool show_disclaimer)
@@ -648,6 +673,7 @@ bool plan(struct diveplan *diveplan, struct dive *dive, int timestep, struct dec
int error = 0;
bool decodive = false;
int first_stop_depth = 0;
+ int laststoptime = timestep;
set_gf(diveplan->gflow, diveplan->gfhigh, prefs.gf_low_at_maxdepth);
set_vpmb_conservatism(diveplan->vpmb_conservatism);
@@ -738,8 +764,8 @@ bool plan(struct diveplan *diveplan, struct dive *dive, int timestep, struct dec
timestep, po2, dive, prefs.bottomsac);
update_cylinder_pressure(dive, depth, depth, timestep, prefs.bottomsac, &dive->cylinder[current_cylinder], false);
clock += timestep;
- } while (trial_ascent(depth, 0, avg_depth, bottom_time, &dive->cylinder[current_cylinder].gasmix,
- po2, diveplan->surface_pressure / 1000.0) &&
+ } while (trial_ascent(0, depth, 0, avg_depth, bottom_time, &dive->cylinder[current_cylinder].gasmix,
+ po2, diveplan->surface_pressure / 1000.0, dive) &&
enough_gas(current_cylinder));
// We did stay one DECOTIMESTEP too many.
@@ -880,8 +906,8 @@ bool plan(struct diveplan *diveplan, struct dive *dive, int timestep, struct dec
if (current_cylinder != gaschanges[gi].gasidx) {
if (!prefs.switch_at_req_stop ||
- !trial_ascent(depth, stoplevels[stopidx - 1], avg_depth, bottom_time,
- &dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0) || get_o2(&dive->cylinder[current_cylinder].gasmix) < 160) {
+ !trial_ascent(0, depth, stoplevels[stopidx - 1], avg_depth, bottom_time,
+ &dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, dive) || get_o2(&dive->cylinder[current_cylinder].gasmix) < 160) {
current_cylinder = gaschanges[gi].gasidx;
gas = dive->cylinder[current_cylinder].gasmix;
#if DEBUG_PLAN & 16
@@ -909,8 +935,8 @@ bool plan(struct diveplan *diveplan, struct dive *dive, int timestep, struct dec
/* Save the current state and try to ascend to the next stopdepth */
while (1) {
/* Check if ascending to next stop is clear, go back and wait if we hit the ceiling on the way */
- if (trial_ascent(depth, stoplevels[stopidx], avg_depth, bottom_time,
- &dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0))
+ if (trial_ascent(0, depth, stoplevels[stopidx], avg_depth, bottom_time,
+ &dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, dive))
break; /* We did not hit the ceiling */
/* Add a minute of deco time and then try again */
@@ -947,14 +973,11 @@ bool plan(struct diveplan *diveplan, struct dive *dive, int timestep, struct dec
pendinggaschange = false;
}
- /* Deco stop should end when runtime is at a whole minute */
- int this_decotimestep;
- this_decotimestep = timestep - clock % timestep;
-
- add_segment(depth_to_bar(depth, dive),
- &dive->cylinder[current_cylinder].gasmix,
- this_decotimestep, po2, dive, prefs.decosac);
- clock += this_decotimestep;
+ int new_clock = wait_until(dive, clock, clock, laststoptime * 2, timestep, depth, stoplevels[stopidx], avg_depth, bottom_time, &dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0);
+ add_segment(depth_to_bar(depth, dive), &dive->cylinder[current_cylinder].gasmix,
+ new_clock - clock, po2, dive, prefs.decosac);
+ laststoptime = new_clock - clock;
+ clock = new_clock;
/* Finish infinite deco */
if (clock >= 48 * 3600 && depth >= 6000) {
error = LONGDECO;