[PATCH] Re: Dive planner oddities

[Robert C. Helling]

Hi, On 12 Oct 2015, at 09:21, Sergey Starosek <sergey.staro...@gmail.com> wrote: Robert, Rick, On Sun, Oct 11, 2015 at 10:44 PM, Rick Walsh <rickmwa...@gmail.com> wrote: The cylinder pressure graph should start to flatten when starting ascent.  Assuming a constant SAC, gas consumption varies with depth.  Is that what you're referring to? See another image attached (rec model, 1 min descent to 30 min, 17 min at 30 m, SAC set to 17/15 l/min). See the pressure graph spike (in red circle). Sergey <Screenshot_2015-10-12_10-05-50.png> this patch should correct this oddity. Best Robert

From b77526a748a026c9ef3accee5a70fc29b7c8af0b Mon Sep 17 00:00:00 2001
From: "Robert C. Helling" <hell...@atdotde.de>
Date: Mon, 12 Oct 2015 22:03:50 +0200
Subject: [PATCH] Don't do a negative time step in recreational mode when
 beyond NDL

In recreational mode, we keep adding time at the last depth
until an ascent does violate the ceiling. Then we roll back
the last added time step and record the ascent. The test for
the ceiling violated was before adding the time so if it alreay
failed the first time we tried to unroll a time step that was
never added which resulted in a small kink in the pressure graph.

This patch corrects this logic by changin a while to a do {} while.

Furthermore, it removes the computation of deco state during the
final ascent since that is not used anywhere later.

Signed-off-by: Robert C. Helling <hell...@atdotde.de>
---
 planner.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/planner.c b/planner.c
index 05fd26e..22d3716 100644
--- a/planner.c
+++ b/planner.c
@@ -1070,15 +1070,21 @@ bool plan(struct diveplan *diveplan, char 
**cached_datap, bool is_planner, bool
                bool safety_stop = prefs.safetystop && max_depth >= 10000;
                track_ascent_gas(depth, 
&displayed_dive.cylinder[current_cylinder], avg_depth, bottom_time, 
safety_stop);
                // How long can we stay at the current depth and still directly 
ascent to the surface?
-               while (trial_ascent(depth, 0, avg_depth, bottom_time, 
&displayed_dive.cylinder[current_cylinder].gasmix,
-                                 po2, diveplan->surface_pressure / 1000.0) &&
-                      enough_gas(current_cylinder)) {
+               do {
                        add_segment(depth_to_bar(depth, &displayed_dive),
-                                                      
&displayed_dive.cylinder[current_cylinder].gasmix,
-                                                      DECOTIMESTEP, po2, 
&displayed_dive, prefs.bottomsac);
+                                   
&displayed_dive.cylinder[current_cylinder].gasmix,
+                                   DECOTIMESTEP, po2, &displayed_dive, 
prefs.bottomsac);
                        update_cylinder_pressure(&displayed_dive, depth, depth, 
DECOTIMESTEP, prefs.bottomsac, &displayed_dive.cylinder[current_cylinder], 
false);
                        clock += DECOTIMESTEP;
-               }
+               } while (trial_ascent(depth, 0, avg_depth, bottom_time, 
&displayed_dive.cylinder[current_cylinder].gasmix,
+                                     po2, diveplan->surface_pressure / 1000.0) 
&&
+                        enough_gas(current_cylinder));
+
+               // We did stay one DECOTIMESTEP too many.
+               // In the best of all worlds, we would roll back also the last 
add_segment in terms of caching deco state, but
+               // let's ignore that since for the eventual ascent in 
recreational mode, nobody looks at the ceiling anymore,
+               // so we don't really have to compute the deco state.
+               update_cylinder_pressure(&displayed_dive, depth, depth, 
-DECOTIMESTEP, prefs.bottomsac, &displayed_dive.cylinder[current_cylinder], 
false);
                clock -= DECOTIMESTEP;
                plan_add_segment(diveplan, clock - previous_point_time, depth, 
gas, po2, true);
                previous_point_time = clock;
@@ -1093,9 +1099,6 @@ bool plan(struct diveplan *diveplan, char **cached_datap, 
bool is_planner, bool
                        if (depth - deltad < 0)
                                deltad = depth;
 
-                       add_segment(depth_to_bar(depth, &displayed_dive),
-                                   
&displayed_dive.cylinder[current_cylinder].gasmix,
-                                   TIMESTEP, po2, &displayed_dive, 
prefs.decosac);
                        clock += TIMESTEP;
                        depth -= deltad;
                        if (depth <= 5000 && depth >= (5000 - deltad) && 
safety_stop) {
-- 
1.9.5 (Apple Git-50.3)

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