Merge branch 'boyle-ready' of https://github.com/Slagvi/subsurface

Fixed merge conflicts in
	deco.c
	dive.h
	planner.c

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

10 files changed, 294 insertions, 156 deletions

diff --git a/deco.c b/deco.c
index 7b0aa54c1..8371dbe11 100644
--- a/deco.c
+++ b/deco.c
@@ -37,14 +37,14 @@ struct buehlmann_config buehlmann_config = { 1.0, 1.01, 0, 0.75, 0.35, 1.0, fals
 struct vpmb_config {
 	double crit_radius_N2;            //! Critical radius of N2 nucleon (microns).
 	double crit_radius_He;            //! Critical radius of He nucleon (microns).
-	double crit_volume_lambda;        //! Constant corresponding to critical gas volume (bar-min).
+	double crit_volume_lambda;        //! Constant corresponding to critical gas volume (bar * min).
 	double gradient_of_imperm;        //! Gradient after which bubbles become impermeable (bar).
-	double surface_tension_gamma;     //! Nucleons surface tension constant.
-	double skin_compression_gammaC;   //! Skin compression gammaC.
+	double surface_tension_gamma;     //! Nucleons surface tension constant (N / 10m).
+	double skin_compression_gammaC;   //! Skin compression gammaC (N / 10m).
 	double regeneration_time;         //! Time needed for the bubble to regenerate to the start radius (min).
 	double other_gases_pressure;      //! Always present pressure of other gasses in tissues (bar).
 };
-struct vpmb_config vpmb_config = { 0.8, 0.7, 230.284, 8.2, 0.179, 2.57, 20160, 0.1359888 };
+struct vpmb_config vpmb_config = { 0.55, 0.45, 230.284, 8.2, 0.179, 2.57, 20160, 0.1359888 };
 
 const double buehlmann_N2_a[] = { 1.1696, 1.0, 0.8618, 0.7562,
 				  0.62, 0.5043, 0.441, 0.4,
@@ -90,8 +90,11 @@ const double buehlmann_He_factor_expositon_one_second[] = {
 	1.00198406028040E-004, 7.83611475491108E-005, 6.13689891868496E-005, 4.81280465299827E-005
 };
 
+const double conservatism_lvls[] = { 1.0, 1.05, 1.12, 1.22, 1.35 };
+
 #define WV_PRESSURE 0.0627 // water vapor pressure in bar
 #define DECO_STOPS_MULTIPLIER_MM 3000.0
+#define NITROGEN_FRACTION 0.79
 
 double tissue_n2_sat[16];
 double tissue_he_sat[16];
@@ -115,6 +118,25 @@ double allowable_n2_gradient[16];
 double allowable_he_gradient[16];
 double total_gradient[16];
 
+double bottom_n2_gradient[16];
+double bottom_he_gradient[16];
+
+double initial_n2_gradient[16];
+double initial_he_gradient[16];
+
+double get_crit_radius_He()
+{
+	if (prefs.conservatism_level <= 4)
+		return vpmb_config.crit_radius_He * conservatism_lvls[prefs.conservatism_level];
+	return vpmb_config.crit_radius_He;
+}
+
+double get_crit_radius_N2()
+{
+	if (prefs.conservatism_level <= 4)
+		return vpmb_config.crit_radius_N2 * conservatism_lvls[prefs.conservatism_level];
+	return vpmb_config.crit_radius_N2;
+}
 
 static double tissue_tolerance_calc(const struct dive *dive)
 {
@@ -223,38 +245,106 @@ double he_factor(int period_in_seconds, int ci)
 	return cache[ci].last_factor;
 }
 
+double calc_surface_phase(double surface_pressure, double he_pressure, double n2_pressure, double he_time_constant, double n2_time_constant)
+{
+	double inspired_n2 = (surface_pressure - WV_PRESSURE) * NITROGEN_FRACTION;
+
+	if (n2_pressure > inspired_n2)
+		return (he_pressure / he_time_constant + (n2_pressure - inspired_n2) / n2_time_constant) / (he_pressure + n2_pressure - inspired_n2);
+
+	if (he_pressure + n2_pressure >= inspired_n2){
+		double gradient_decay_time = 1.0 / (n2_time_constant - he_time_constant) * log ((inspired_n2 - n2_pressure) / he_pressure);
+		double gradients_integral = he_pressure / he_time_constant * (1.0 - exp(-he_time_constant * gradient_decay_time)) + (n2_pressure - inspired_n2) / n2_time_constant * (1.0 - exp(-n2_time_constant * gradient_decay_time));
+		return gradients_integral / (he_pressure + n2_pressure - inspired_n2);
+	}
+
+	return 0;
+}
+
+bool is_vpmb_ok(double pressure)
+{
+	int ci;
+	double gradient;
+	double gas_tension;
+
+	for (ci = 0; ci < 16; ++ci) {
+		gas_tension = tissue_n2_sat[ci] + tissue_he_sat[ci] + vpmb_config.other_gases_pressure;
+		gradient = gas_tension - pressure;
+		if (gradient > total_gradient[ci])
+			return false;
+	}
+	return true;
+}
+
 void vpmb_start_gradient()
 {
 	int ci;
 	double gradient_n2, gradient_he;
 
 	for (ci = 0; ci < 16; ++ci) {
-		allowable_n2_gradient[ci] = 2.0 * (vpmb_config.surface_tension_gamma / vpmb_config.skin_compression_gammaC) * ((vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma) / n2_regen_radius[ci]);
-		allowable_he_gradient[ci] = 2.0 * (vpmb_config.surface_tension_gamma / vpmb_config.skin_compression_gammaC) * ((vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma) / he_regen_radius[ci]);
+		initial_n2_gradient[ci] = bottom_n2_gradient[ci] = allowable_n2_gradient[ci] = 2.0 * (vpmb_config.surface_tension_gamma / vpmb_config.skin_compression_gammaC) * ((vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma) / n2_regen_radius[ci]);
+		initial_he_gradient[ci] = bottom_he_gradient[ci] = allowable_he_gradient[ci] = 2.0 * (vpmb_config.surface_tension_gamma / vpmb_config.skin_compression_gammaC) * ((vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma) / he_regen_radius[ci]);
 
 		total_gradient[ci] = ((allowable_n2_gradient[ci] * tissue_n2_sat[ci]) + (allowable_he_gradient[ci] * tissue_he_sat[ci])) / (tissue_n2_sat[ci] + tissue_he_sat[ci]);
 	}
 }
 
-void vpmb_next_gradient(double deco_time)
+void vpmb_next_gradient(double deco_time, double surface_pressure)
 {
 	int ci;
 	double gradient_n2, gradient_he;
 	double n2_b, n2_c;
 	double he_b, he_c;
-	deco_time /= 60.0 ;
+	double desat_time;
+	deco_time /= 60.0;
 
 	for (ci = 0; ci < 16; ++ci) {
-		n2_b = allowable_n2_gradient[ci] + ((vpmb_config.crit_volume_lambda * vpmb_config.surface_tension_gamma) / (vpmb_config.skin_compression_gammaC * (deco_time + buehlmann_N2_t_halflife[ci] * 60.0 / log(2.0))));
-		he_b = allowable_he_gradient[ci] + ((vpmb_config.crit_volume_lambda * vpmb_config.surface_tension_gamma) / (vpmb_config.skin_compression_gammaC * (deco_time + buehlmann_He_t_halflife[ci] * 60.0 / log(2.0))));
+		desat_time = deco_time + calc_surface_phase(surface_pressure, tissue_he_sat[ci], tissue_n2_sat[ci], log(2.0) / buehlmann_He_t_halflife[ci], log(2.0) / buehlmann_N2_t_halflife[ci]);
+
+		n2_b = initial_n2_gradient[ci] + (vpmb_config.crit_volume_lambda * vpmb_config.surface_tension_gamma) / (vpmb_config.skin_compression_gammaC * desat_time);
+		he_b = initial_he_gradient[ci] + (vpmb_config.crit_volume_lambda * vpmb_config.surface_tension_gamma) / (vpmb_config.skin_compression_gammaC * desat_time);
 
 		n2_c = vpmb_config.surface_tension_gamma * vpmb_config.surface_tension_gamma * vpmb_config.crit_volume_lambda * max_n2_crushing_pressure[ci];
-		n2_c = n2_c / (vpmb_config.skin_compression_gammaC * vpmb_config.skin_compression_gammaC * (deco_time + buehlmann_N2_t_halflife[ci] * 60.0 / log(2.0)));
+		n2_c = n2_c / (vpmb_config.skin_compression_gammaC * vpmb_config.skin_compression_gammaC * desat_time);
 		he_c = vpmb_config.surface_tension_gamma * vpmb_config.surface_tension_gamma * vpmb_config.crit_volume_lambda * max_he_crushing_pressure[ci];
-		he_c = he_c / (vpmb_config.skin_compression_gammaC * vpmb_config.skin_compression_gammaC * (deco_time + buehlmann_He_t_halflife[ci] * 60.0 / log(2.0)));
+		he_c = he_c / (vpmb_config.skin_compression_gammaC * vpmb_config.skin_compression_gammaC * desat_time);
+
+		bottom_n2_gradient[ci] = allowable_n2_gradient[ci] = 0.5 * ( n2_b + sqrt(n2_b * n2_b - 4.0 * n2_c));
+		bottom_he_gradient[ci] = allowable_he_gradient[ci] = 0.5 * ( he_b + sqrt(he_b * he_b - 4.0 * he_c));
 
-		allowable_n2_gradient[ci] = 0.5 * ( n2_b + sqrt(n2_b * n2_b - 4.0 * n2_c));
-		allowable_he_gradient[ci] = 0.5 * ( he_b + sqrt(he_b * he_b - 4.0 * he_c));
+		total_gradient[ci] = ((allowable_n2_gradient[ci] * tissue_n2_sat[ci]) + (allowable_he_gradient[ci] * tissue_he_sat[ci])) / (tissue_n2_sat[ci] + tissue_he_sat[ci]);
+	}
+}
+
+double update_gradient(double first_stop_pressure, double next_stop_pressure, double first_gradient)
+{
+	double first_radius = 2.0 * vpmb_config.surface_tension_gamma / first_gradient;
+	double A = next_stop_pressure;
+	double B = -2.0 * vpmb_config.surface_tension_gamma;
+	double C = (first_stop_pressure + 2.0 * vpmb_config.surface_tension_gamma / first_radius) * pow(first_radius, 3.0);
+
+	double low = first_radius;
+	double high = first_radius * pow(first_stop_pressure / next_stop_pressure, (1.0/3.0));
+	double next_radius;
+	double value;
+	int ci;
+	for (ci = 0; ci < 100; ++ci){
+		next_radius = (high + low) /2.0;
+		value = A * pow(next_radius, 3.0) - B * next_radius * next_radius - C;
+		if (value < 0)
+			low = next_radius;
+		else
+			high = next_radius;
+	}
+	return 2.0 * vpmb_config.surface_tension_gamma / next_radius;
+}
+
+void boyles_law(double first_stop_pressure, double next_stop_pressure)
+{
+	int ci;
+	for (ci = 0; ci < 16; ++ci) {
+		allowable_n2_gradient[ci] = update_gradient(first_stop_pressure, next_stop_pressure, bottom_n2_gradient[ci]);
+		allowable_he_gradient[ci] = update_gradient(first_stop_pressure, next_stop_pressure, bottom_he_gradient[ci]);
 
 		total_gradient[ci] = ((allowable_n2_gradient[ci] * tissue_n2_sat[ci]) + (allowable_he_gradient[ci] * tissue_he_sat[ci])) / (tissue_n2_sat[ci] + tissue_he_sat[ci]);
 	}
@@ -267,11 +357,11 @@ void nuclear_regeneration(double time)
 	double crushing_radius_N2, crushing_radius_He;
 	for (ci = 0; ci < 16; ++ci) {
 		//rm
-		crushing_radius_N2 = 1.0 / (max_n2_crushing_pressure[ci] / (2.0 * (vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma)) + 1.0 / vpmb_config.crit_radius_N2);
-		crushing_radius_He = 1.0 / (max_he_crushing_pressure[ci] / (2.0 * (vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma)) + 1.0 / vpmb_config.crit_radius_He);
+		crushing_radius_N2 = 1.0 / (max_n2_crushing_pressure[ci] / (2.0 * (vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma)) + 1.0 / get_crit_radius_N2());
+		crushing_radius_He = 1.0 / (max_he_crushing_pressure[ci] / (2.0 * (vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma)) + 1.0 / get_crit_radius_He());
 		//rs
-		n2_regen_radius[ci] = crushing_radius_N2 + (vpmb_config.crit_radius_N2 - crushing_radius_N2) * (1.0 - exp (-time / vpmb_config.regeneration_time));
-		he_regen_radius[ci] = crushing_radius_He + (vpmb_config.crit_radius_He - crushing_radius_He) * (1.0 - exp (-time / vpmb_config.regeneration_time));
+		n2_regen_radius[ci] = crushing_radius_N2 + (get_crit_radius_N2() - crushing_radius_N2) * (1.0 - exp (-time / vpmb_config.regeneration_time));
+		he_regen_radius[ci] = crushing_radius_He + (get_crit_radius_He() - crushing_radius_He) * (1.0 - exp (-time / vpmb_config.regeneration_time));
 	}
 }
 
@@ -325,8 +415,8 @@ void calc_crushing_pressure(double pressure)
 			if (max_ambient_pressure >= pressure)
 				return;
 
-			n2_inner_pressure = calc_inner_pressure(vpmb_config.crit_radius_N2, crushing_onset_tension[ci], pressure);
-			he_inner_pressure = calc_inner_pressure(vpmb_config.crit_radius_He, crushing_onset_tension[ci], pressure);
+			n2_inner_pressure = calc_inner_pressure(get_crit_radius_N2(), crushing_onset_tension[ci], pressure);
+			he_inner_pressure = calc_inner_pressure(get_crit_radius_He(), crushing_onset_tension[ci], pressure);
 
 			n2_crushing_pressure = pressure - n2_inner_pressure;
 			he_crushing_pressure = pressure - he_inner_pressure;
diff --git a/dive.h b/dive.h
index d0ef47ded..d5681f163 100644
--- a/dive.h
+++ b/dive.h
@@ -800,7 +800,9 @@ extern void cache_deco_state(double, char **datap);
 extern double restore_deco_state(char *data);
 extern void nuclear_regeneration(double time);
 extern void vpmb_start_gradient();
-extern void vpmb_next_gradient(double deco_time);
+extern void vpmb_next_gradient(double deco_time, double surface_pressure);
+extern bool is_vpmb_ok(double pressure);
+extern void boyles_law(double first_stop_pressure, double next_stop_pressure);
 
 /* this should be converted to use our types */
 struct divedatapoint {
diff --git a/planner.c b/planner.c
index 3c09a610a..d6efb61f1 100644
--- a/planner.c
+++ b/planner.c
@@ -892,6 +892,10 @@ bool trial_ascent(int trial_depth, int stoplevel, int avg_depth, int bottom_time
 			clear_to_ascend = false;
 			break;
 		}
+		if (prefs.deco_mode == VPMB && (!is_vpmb_ok(depth_to_mbar(trial_depth - deltad, &displayed_dive) / 1000.0))){
+			clear_to_ascend = false;
+			break;
+		}
 		trial_depth -= deltad;
 	}
 	restore_deco_state(trial_cache);
@@ -923,6 +927,7 @@ bool plan(struct diveplan *diveplan, char **cached_datap, bool is_planner, bool
 	int bottom_depth;
 	int bottom_gi;
 	int bottom_stopidx;
+	int first_stop_pressure;
 	bool is_final_plan = true;
 	int deco_time;
 	int previous_deco_time;
@@ -1102,6 +1107,9 @@ bool plan(struct diveplan *diveplan, char **cached_datap, bool is_planner, bool
 	//CVA
 	do {
 		is_final_plan = (prefs.deco_mode == BUEHLMANN) || (previous_deco_time - deco_time < 10);  // CVA time converges
+		if (deco_time != 10000000)
+			vpmb_next_gradient(deco_time, diveplan->surface_pressure / 1000.0);
+
 		previous_deco_time = deco_time;
 		restore_deco_state(bottom_cache);
 
@@ -1115,12 +1123,12 @@ bool plan(struct diveplan *diveplan, char **cached_datap, bool is_planner, bool
 		breaktime = -1;
 		breakcylinder = 0;
 		o2time = 0;
+		first_stop_pressure = 0;
 		last_ascend_rate = ascent_velocity(depth, avg_depth, bottom_time);
 		if ((current_cylinder = get_gasidx(&displayed_dive, &gas)) == -1) {
 			report_error(translate("gettextFromC", "Can't find gas %s"), gasname(&gas));
 			current_cylinder = 0;
 		}
-		vpmb_next_gradient(deco_time);
 
 		while (1) {
 			/* We will break out when we hit the surface */
@@ -1204,6 +1212,11 @@ bool plan(struct diveplan *diveplan, char **cached_datap, bool is_planner, bool
 						plan_add_segment(diveplan, clock - previous_point_time, depth, gas, po2, false);
 					previous_point_time = clock;
 					stopping = true;
+
+					// Boyles Law compensation
+					if (first_stop_pressure == 0)
+						first_stop_pressure = depth_to_mbar(depth, &displayed_dive);
+					boyles_law(first_stop_pressure / 1000.0, depth_to_mbar(stoplevels[stopidx], &displayed_dive) / 1000.0);
 				}
 
 				/* Are we waiting to switch gas?
diff --git a/pref.h b/pref.h
index 3791f62e7..e471add73 100644
--- a/pref.h
+++ b/pref.h
@@ -117,6 +117,7 @@ struct preferences {
 	bool cloud_background_sync;
 	geocoding_prefs_t geocoding;
 	enum deco_mode deco_mode;
+	short conservatism_level;
 };
 enum unit_system_values {
 	METRIC,
diff --git a/qt-models/diveplannermodel.cpp b/qt-models/diveplannermodel.cpp
index e82daba11..005061feb 100644
--- a/qt-models/diveplannermodel.cpp
+++ b/qt-models/diveplannermodel.cpp
@@ -397,6 +397,12 @@ void DivePlannerPointsModel::triggerGFLow()
 	}
 }
 
+void DivePlannerPointsModel::setConservatism(int level)
+{
+	prefs.conservatism_level = level;
+	emit dataChanged(createIndex(0, 0), createIndex(rowCount() - 1, COLUMNS - 1));
+}
+
 void DivePlannerPointsModel::setSurfacePressure(int pressure)
 {
 	diveplan.surface_pressure = pressure;
diff --git a/qt-models/diveplannermodel.h b/qt-models/diveplannermodel.h
index a8524393a..b87ed84c3 100644
--- a/qt-models/diveplannermodel.h
+++ b/qt-models/diveplannermodel.h
@@ -65,6 +65,7 @@ slots:
 	void triggerGFHigh();
 	void setGFLow(const int ghflow);
 	void triggerGFLow();
+	void setConservatism(int level);
 	void setSurfacePressure(int pressure);
 	void setSalinity(int salinity);
 	int getSurfacePressure();
diff --git a/qt-ui/diveplanner.cpp b/qt-ui/diveplanner.cpp
index efa75ddec..82ecb05dc 100644
--- a/qt-ui/diveplanner.cpp
+++ b/qt-ui/diveplanner.cpp
@@ -217,32 +217,37 @@ void PlannerSettingsWidget::decoSacChanged(const double decosac)
 	plannerModel->setDecoSac(decosac);
 }
 
-void PlannerSettingsWidget::disableDecoElements(bool value)
-{
-	if (prefs.deco_mode == RECREATIONAL) {
-		ui.lastStop->setDisabled(value);
-		ui.backgasBreaks->setDisabled(value);
-		ui.bottompo2->setDisabled(value);
-		ui.decopo2->setDisabled(value);
-		ui.reserve_gas->setDisabled(!value);
+void PlannerSettingsWidget::disableDecoElements(int mode)
+{
+	if (mode == RECREATIONAL) {
+		ui.gflow->setDisabled(false);
+		ui.gfhigh->setDisabled(false);
+		ui.lastStop->setDisabled(true);
+		ui.backgasBreaks->setDisabled(true);
+		ui.bottompo2->setDisabled(true);
+		ui.decopo2->setDisabled(true);
+		ui.reserve_gas->setDisabled(false);
+		ui.conservatism_lvl->setDisabled(true);
 	}
-	else if (prefs.deco_mode == VPMB) {
-		ui.gflow->setDisabled(value);
-		ui.gfhigh->setDisabled(value);
-		ui.lastStop->setDisabled(!value);
-		ui.backgasBreaks->setDisabled(!value);
-		ui.bottompo2->setDisabled(!value);
-		ui.decopo2->setDisabled(!value);
-		ui.reserve_gas->setDisabled(value);
+	else if (mode == VPMB) {
+		ui.gflow->setDisabled(true);
+		ui.gfhigh->setDisabled(true);
+		ui.lastStop->setDisabled(false);
+		ui.backgasBreaks->setDisabled(false);
+		ui.bottompo2->setDisabled(false);
+		ui.decopo2->setDisabled(false);
+		ui.reserve_gas->setDisabled(true);
+		ui.conservatism_lvl->setDisabled(false);
 	}
-	else if (prefs.deco_mode == BUEHLMANN) {
-		ui.gflow->setDisabled(!value);
-		ui.gfhigh->setDisabled(!value);
-		ui.lastStop->setDisabled(!value);
-		ui.backgasBreaks->setDisabled(!value);
-		ui.bottompo2->setDisabled(!value);
-		ui.decopo2->setDisabled(!value);
-		ui.reserve_gas->setDisabled(value);
+	else if (mode == BUEHLMANN) {
+		ui.gflow->setDisabled(false);
+		ui.gfhigh->setDisabled(false);
+		ui.lastStop->setDisabled(false);
+		ui.backgasBreaks->setDisabled(false);
+		ui.bottompo2->setDisabled(false);
+		ui.decopo2->setDisabled(false);
+		ui.reserve_gas->setDisabled(true);
+		ui.conservatism_lvl->setDisabled(true);
 	}
 }
 
@@ -279,6 +284,7 @@ PlannerSettingsWidget::PlannerSettingsWidget(QWidget *parent, Qt::WindowFlags f)
 	prefs.drop_stone_mode = s.value("drop_stone_mode", prefs.drop_stone_mode).toBool();
 	prefs.bottomsac = s.value("bottomsac", prefs.bottomsac).toInt();
 	prefs.decosac = s.value("decosac", prefs.decosac).toInt();
+	prefs.conservatism_level = s.value("conservatism", prefs.conservatism_level).toInt();
 	plannerModel->getDiveplan().bottomsac = prefs.bottomsac;
 	plannerModel->getDiveplan().decosac = prefs.decosac;
 	s.endGroup();
@@ -300,6 +306,8 @@ PlannerSettingsWidget::PlannerSettingsWidget(QWidget *parent, Qt::WindowFlags f)
 	ui.recreational_deco->setChecked(prefs.deco_mode == RECREATIONAL);
 	ui.buehlmann_deco->setChecked(prefs.deco_mode == BUEHLMANN);
 	ui.vpmb_deco->setChecked(prefs.deco_mode == VPMB);
+	ui.conservatism_lvl->setValue(prefs.conservatism_level);
+	disableDecoElements((int) prefs.deco_mode);
 
 	// should be the same order as in dive_comp_type!
 	rebreather_modes << tr("Open circuit") << tr("CCR") << tr("pSCR");
@@ -341,11 +349,12 @@ PlannerSettingsWidget::PlannerSettingsWidget(QWidget *parent, Qt::WindowFlags f)
 	connect(ui.gflow, SIGNAL(valueChanged(int)), plannerModel, SLOT(setGFLow(int)));
 	connect(ui.gfhigh, SIGNAL(editingFinished()), plannerModel, SLOT(triggerGFHigh()));
 	connect(ui.gflow, SIGNAL(editingFinished()), plannerModel, SLOT(triggerGFLow()));
+	connect(ui.conservatism_lvl, SIGNAL(valueChanged(int)), plannerModel, SLOT(setConservatism(int)));
 	connect(ui.backgasBreaks, SIGNAL(toggled(bool)), this, SLOT(setBackgasBreaks(bool)));
 	connect(ui.switch_at_req_stop, SIGNAL(toggled(bool)), plannerModel, SLOT(setSwitchAtReqStop(bool)));
 	connect(ui.min_switch_duration, SIGNAL(valueChanged(int)), plannerModel, SLOT(setMinSwitchDuration(int)));
 	connect(ui.rebreathermode, SIGNAL(currentIndexChanged(int)), plannerModel, SLOT(setRebreatherMode(int)));
-	connect(plannerModel, SIGNAL(recreationChanged(bool)), this, SLOT(disableDecoElements(bool)));
+	connect(modeMapper, SIGNAL(mapped(int)), this, SLOT(disableDecoElements(int)));
 
 	settingsChanged();
 	ui.gflow->setValue(prefs.gflow);
@@ -389,6 +398,7 @@ PlannerSettingsWidget::~PlannerSettingsWidget()
 	s.setValue("bottomsac", prefs.bottomsac);
 	s.setValue("decosac", prefs.decosac);
 	s.setValue("deco_mode", int(prefs.deco_mode));
+	s.setValue("conservatism", prefs.conservatism_level);
 	s.endGroup();
 }
 
diff --git a/qt-ui/diveplanner.h b/qt-ui/diveplanner.h
index c4210aadf..b2e03a97b 100644
--- a/qt-ui/diveplanner.h
+++ b/qt-ui/diveplanner.h
@@ -80,7 +80,7 @@ slots:
 	void setBottomPo2(double po2);
 	void setDecoPo2(double po2);
 	void setBackgasBreaks(bool dobreaks);
-	void disableDecoElements(bool value);
+	void disableDecoElements(int mode);
 
 private:
 	Ui::plannerSettingsWidget ui;
diff --git a/qt-ui/plannerSettings.ui b/qt-ui/plannerSettings.ui
index 3287b84fb..4ebc868af 100644
--- a/qt-ui/plannerSettings.ui
+++ b/qt-ui/plannerSettings.ui
@@ -255,94 +255,49 @@
           <property name="spacing">
            <number>2</number>
           </property>
-          <item row="17" column="1">
-           <widget class="QLabel" name="label_4">
-            <property name="text">
-             <string>Min. switch duration</string>
-            </property>
-           </widget>
-          </item>
-          <item row="19" column="1">
-           <spacer name="verticalSpacer_2">
-            <property name="orientation">
-             <enum>Qt::Vertical</enum>
-            </property>
-            <property name="sizeHint" stdset="0">
-             <size>
-              <width>20</width>
-              <height>40</height>
-             </size>
-            </property>
-           </spacer>
-          </item>
-          <item row="18" column="1">
-           <widget class="QComboBox" name="rebreathermode">
-            <property name="currentText">
-             <string/>
-            </property>
-            <property name="maxVisibleItems">
-             <number>6</number>
-            </property>
-           </widget>
-          </item>
-          <item row="8" column="2">
-           <widget class="QSpinBox" name="gflow">
-            <property name="suffix">
-             <string>%</string>
-            </property>
-            <property name="minimum">
-             <number>1</number>
-            </property>
-            <property name="maximum">
-             <number>150</number>
-            </property>
-           </widget>
-          </item>
-          <item row="13" column="1" colspan="2">
-           <widget class="QCheckBox" name="drop_stone_mode">
+          <item row="11" column="1">
+           <widget class="QRadioButton" name="vpmb_deco">
             <property name="text">
-             <string>Drop to first depth</string>
+             <string>VPM-B deco</string>
             </property>
            </widget>
           </item>
-          <item row="14" column="1" colspan="2">
-           <widget class="QCheckBox" name="lastStop">
+          <item row="4" column="1">
+           <widget class="QRadioButton" name="buehlmann_deco">
             <property name="text">
-             <string>Last stop at 6m</string>
+             <string>Buehlmann deco</string>
             </property>
-           </widget>
-          </item>
-          <item row="0" column="1">
-           <widget class="QRadioButton" name="recreational_deco">
-            <property name="text">
-             <string>Recreational mode</string>
+            <property name="checked">
+             <bool>true</bool>
             </property>
            </widget>
           </item>
-          <item row="8" column="1">
-           <widget class="QLabel" name="label_15">
+          <item row="1" column="1">
+           <widget class="QLabel" name="label_3">
             <property name="text">
-             <string>GF low</string>
+             <string>Reserve gas</string>
             </property>
             <property name="indent">
              <number>26</number>
             </property>
            </widget>
           </item>
-          <item row="15" column="1" colspan="2">
-           <widget class="QCheckBox" name="backgasBreaks">
-            <property name="text">
-             <string>Plan backgas breaks</string>
+          <item row="1" column="2">
+           <widget class="QSpinBox" name="reserve_gas">
+            <property name="suffix">
+             <string>bar</string>
             </property>
-           </widget>
-          </item>
-          <item row="9" column="1">
-           <widget class="QLabel" name="label_16">
-            <property name="text">
-             <string>GF high</string>
+            <property name="prefix">
+             <string/>
             </property>
-            <property name="indent">
-             <number>25</number>
+            <property name="minimum">
+             <number>10</number>
+            </property>
+            <property name="maximum">
+             <number>99</number>
+            </property>
+            <property name="value">
+             <number>40</number>
             </property>
            </widget>
           </item>
@@ -359,7 +314,7 @@
             </property>
            </widget>
           </item>
-          <item row="16" column="1" colspan="2">
+          <item row="17" column="1" colspan="2">
            <widget class="QCheckBox" name="switch_at_req_stop">
             <property name="toolTip">
              <string>Postpone gas change if a stop is not required</string>
@@ -382,20 +337,34 @@
             </property>
            </spacer>
           </item>
-          <item row="12" column="1">
-           <spacer name="verticalSpacer_5">
-            <property name="orientation">
-             <enum>Qt::Vertical</enum>
+          <item row="8" column="1">
+           <widget class="QLabel" name="label_15">
+            <property name="text">
+             <string>GF low</string>
             </property>
-            <property name="sizeHint" stdset="0">
-             <size>
-              <width>20</width>
-              <height>20</height>
-             </size>
+            <property name="indent">
+             <number>26</number>
             </property>
-           </spacer>
+           </widget>
+          </item>
+          <item row="16" column="1" colspan="2">
+           <widget class="QCheckBox" name="backgasBreaks">
+            <property name="text">
+             <string>Plan backgas breaks</string>
+            </property>
+           </widget>
           </item>
-          <item row="17" column="2">
+          <item row="9" column="1">
+           <widget class="QLabel" name="label_16">
+            <property name="text">
+             <string>GF high</string>
+            </property>
+            <property name="indent">
+             <number>25</number>
+            </property>
+           </widget>
+          </item>
+          <item row="18" column="2">
            <widget class="QSpinBox" name="min_switch_duration">
             <property name="suffix">
              <string>min</string>
@@ -414,52 +383,70 @@
             </property>
            </widget>
           </item>
-          <item row="11" column="1">
-           <widget class="QRadioButton" name="vpmb_deco">
+          <item row="15" column="1" colspan="2">
+           <widget class="QCheckBox" name="lastStop">
             <property name="text">
-             <string>VPM-B deco</string>
+             <string>Last stop at 6m</string>
             </property>
            </widget>
           </item>
-          <item row="4" column="1">
-           <widget class="QRadioButton" name="buehlmann_deco">
+          <item row="0" column="1">
+           <widget class="QRadioButton" name="recreational_deco">
             <property name="text">
-             <string>Buehlmann deco</string>
-            </property>
-            <property name="checked">
-             <bool>true</bool>
+             <string>Recreational mode</string>
             </property>
            </widget>
           </item>
-          <item row="1" column="1">
-           <widget class="QLabel" name="label_3">
-            <property name="text">
-             <string>Reserve gas</string>
+          <item row="19" column="1">
+           <widget class="QComboBox" name="rebreathermode">
+            <property name="currentText" stdset="0">
+             <string/>
             </property>
-            <property name="indent">
-             <number>26</number>
+            <property name="maxVisibleItems">
+             <number>6</number>
             </property>
            </widget>
           </item>
-          <item row="1" column="2">
-           <widget class="QSpinBox" name="reserve_gas">
+          <item row="8" column="2">
+           <widget class="QSpinBox" name="gflow">
             <property name="suffix">
-             <string>bar</string>
-            </property>
-            <property name="prefix">
-             <string/>
+             <string>%</string>
             </property>
             <property name="minimum">
-             <number>10</number>
+             <number>1</number>
             </property>
             <property name="maximum">
-             <number>99</number>
+             <number>150</number>
             </property>
-            <property name="value">
-             <number>40</number>
+           </widget>
+          </item>
+          <item row="14" column="1" colspan="2">
+           <widget class="QCheckBox" name="drop_stone_mode">
+            <property name="text">
+             <string>Drop to first depth</string>
             </property>
            </widget>
           </item>
+          <item row="18" column="1">
+           <widget class="QLabel" name="label_4">
+            <property name="text">
+             <string>Min. switch duration</string>
+            </property>
+           </widget>
+          </item>
+          <item row="20" column="1">
+           <spacer name="verticalSpacer_2">
+            <property name="orientation">
+             <enum>Qt::Vertical</enum>
+            </property>
+            <property name="sizeHint" stdset="0">
+             <size>
+              <width>20</width>
+              <height>40</height>
+             </size>
+            </property>
+           </spacer>
+          </item>
           <item row="2" column="1" alignment="Qt::AlignHCenter">
            <widget class="QCheckBox" name="safetystop">
             <property name="layoutDirection">
@@ -486,6 +473,33 @@
             </property>
            </spacer>
           </item>
+          <item row="13" column="1">
+           <spacer name="verticalSpacer_5">
+            <property name="orientation">
+             <enum>Qt::Vertical</enum>
+            </property>
+            <property name="sizeHint" stdset="0">
+             <size>
+              <width>20</width>
+              <height>20</height>
+             </size>
+            </property>
+           </spacer>
+          </item>
+          <item row="12" column="1">
+           <widget class="QLabel" name="label_5">
+            <property name="text">
+             <string>Conservatism level</string>
+            </property>
+           </widget>
+          </item>
+          <item row="12" column="2">
+           <widget class="QSpinBox" name="conservatism_lvl">
+            <property name="maximum">
+             <number>4</number>
+            </property>
+           </widget>
+          </item>
          </layout>
         </widget>
        </item>
diff --git a/subsurfacestartup.c b/subsurfacestartup.c
index 17bd43e45..18d00d374 100644
--- a/subsurfacestartup.c
+++ b/subsurfacestartup.c
@@ -75,7 +75,8 @@ struct preferences default_prefs = {
 		.tag_existing_dives = false,
 		.category = { 0 }
 	},
-	.deco_mode = BUEHLMANN
+	.deco_mode = BUEHLMANN,
+	.conservatism_level = 0
 };
 
 int run_survey;