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authorGravatar Robert C. Helling <helling@atdotde.de>2016-08-30 11:33:16 +0200
committerGravatar Dirk Hohndel <dirk@hohndel.org>2016-09-17 13:41:12 -0700
commitcd99bbe727e31222a0cfb127f0b5acc7464b9800 (patch)
tree1fd24f566aa99f533943c9926a35ffe6203042e4 /core
parent893bea700c982daacb0af2feec4b2ac98c96424f (diff)
downloadsubsurface-cd99bbe727e31222a0cfb127f0b5acc7464b9800.tar.gz
Cosmetic changes to Buehlmann code
Change runtime table string from ZHL-16B to ZHL-16C to reflect he fact that we use 5min as half-time for the fastest compartment rather than 4min. Further more trade pow(2.0, ...) for exp(). Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Diffstat (limited to 'core')
-rw-r--r--core/deco.c7
-rw-r--r--core/planner.c2
2 files changed, 6 insertions, 3 deletions
diff --git a/core/deco.c b/core/deco.c
index af3e06126..b86376cae 100644
--- a/core/deco.c
+++ b/core/deco.c
@@ -91,6 +91,7 @@ const double buehlmann_N2_t_halflife[] = { 5.0, 8.0, 12.5, 18.5,
109.0, 146.0, 187.0, 239.0,
305.0, 390.0, 498.0, 635.0 };
+// 1 - exp(-1 / (halflife * 60) * ln(2))
const double buehlmann_N2_factor_expositon_one_second[] = {
2.30782347297664E-003, 1.44301447809736E-003, 9.23769302935806E-004, 6.24261986779007E-004,
4.27777107246730E-004, 3.01585140931371E-004, 2.12729727268379E-004, 1.50020603047807E-004,
@@ -329,7 +330,8 @@ double n2_factor(int period_in_seconds, int ci)
if (period_in_seconds != cache[ci].last_period) {
cache[ci].last_period = period_in_seconds;
- cache[ci].last_factor = 1 - pow(2.0, -period_in_seconds / (buehlmann_N2_t_halflife[ci] * 60));
+ // ln(2)/60 = 1.155245301e-02
+ cache[ci].last_factor = 1 - exp(-period_in_seconds * 1.155245301e-02 / buehlmann_N2_t_halflife[ci]);
}
return cache[ci].last_factor;
@@ -344,7 +346,8 @@ double he_factor(int period_in_seconds, int ci)
if (period_in_seconds != cache[ci].last_period) {
cache[ci].last_period = period_in_seconds;
- cache[ci].last_factor = 1 - pow(2.0, -period_in_seconds / (buehlmann_He_t_halflife[ci] * 60));
+ // ln(2)/60 = 1.155245301e-02
+ cache[ci].last_factor = 1 - exp(-period_in_seconds * 1.155245301e-02 / buehlmann_He_t_halflife[ci]);
}
return cache[ci].last_factor;
diff --git a/core/planner.c b/core/planner.c
index fe9176950..bbc1599e7 100644
--- a/core/planner.c
+++ b/core/planner.c
@@ -562,7 +562,7 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
len = show_disclaimer ? snprintf(buffer, sz_buffer, "<div><b>%s<b></div><br>", disclaimer) : 0;
if (prefs.deco_mode == BUEHLMANN){
- snprintf(temp, sz_temp, translate("gettextFromC", "based on Bühlmann ZHL-16B with GFlow = %d and GFhigh = %d"),
+ snprintf(temp, sz_temp, translate("gettextFromC", "based on Bühlmann ZHL-16C with GFlow = %d and GFhigh = %d"),
diveplan->gflow, diveplan->gfhigh);
} else if (prefs.deco_mode == VPMB){
if (prefs.conservatism_level == 0)