[PATCH 2/2] VPM-B: Get rid of ugly blips in ceiling

[Rick Walsh]

A real ceiling is the ceiling calculated when the ambient pressure is at the
ceiling.  As such, the Boyle's law compensation should be done against the
ambient pressure at the ceiling.  Instead of doing an iterative calculation,
take the lesser ambient pressure of the ceiling of the previous sample, and the
depth of the current sample.

This approach gets rid of "blips" in the calculated ceiling due to a step in
Boyle's law compensation during ascent.  In limited testing, it also appears to
avoid creating a ceiling deeper than the calculated plan in most cases.

Signed-off-by: Rick Walsh <rickmwalsh at gmail.com>
---
 profile.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/profile.c b/profile.c
index 79effeb..79308e7 100644
--- a/profile.c
+++ b/profile.c
@@ -853,13 +853,13 @@ void calculate_deco_information(struct dive *dive, struct divecomputer *dc, stru
 			time_stepsize = t1 - t0;
 		for (j = t0 + time_stepsize; j <= t1; j += time_stepsize) {
 			int depth = interpolate(entry[-1].depth, entry[0].depth, j - t0, t1 - t0);
-			boyles_law(depth_to_mbar(entry->depth, &displayed_dive) / 1000.0);
 			double min_pressure = add_segment(depth_to_mbar(depth, dive) / 1000.0,
 							  &dive->cylinder[entry->cylinderindex].gasmix, time_stepsize, entry->o2pressure.mbar, dive, entry->sac);
 			tissue_tolerance = min_pressure;
 			if ((t1 - j < time_stepsize) && (j < t1))
 				time_stepsize = t1 - j;
 		}
+		boyles_law(depth_to_mbar((entry - 1)->ceiling, &displayed_dive) / 1000.0);
 		if (t0 == t1)
 			entry->ceiling = (entry - 1)->ceiling;
 		else
-- 
2.4.3