From 7da8368995c5565513524c4f671e21f8c8272271 Mon Sep 17 00:00:00 2001 From: "Robert C. Helling" Date: Mon, 19 Jan 2015 11:32:27 +0100 Subject: [PATCH] Use SAC from preferences for PSCR oxygen drop The ratio between SAC and oxygen metabolism rate can be assumed constant but not the metabolism rate. So we better base our calculation on the ratio that uses the SAC from the preferences as that pairs well with the O2 consumption from the preferences. Hence we ran remove the sac parameter from fill_pressures(). Signed-off-by: Robert C. Helling --- deco.c | 2 +- dive.c | 17 ++++++----------- dive.h | 2 +- profile.c | 2 +- 4 files changed, 9 insertions(+), 14 deletions(-) diff --git a/deco.c b/deco.c index 14f88f6..9d0ec9d 100644 --- a/deco.c +++ b/deco.c @@ -190,7 +190,7 @@ double add_segment(double pressure, const struct gasmix *gasmix, int period_in_s int ci; struct gas_pressures pressures; - fill_pressures(&pressures, pressure - WV_PRESSURE, gasmix, (double) ccpo2 / 1000.0, dive->dc.divemode, sac); + fill_pressures(&pressures, pressure - WV_PRESSURE, gasmix, (double) ccpo2 / 1000.0, dive->dc.divemode); if (buehlmann_config.gf_low_at_maxdepth && pressure > gf_low_pressure_this_dive) gf_low_pressure_this_dive = pressure; diff --git a/dive.c b/dive.c index 33e3fb2..a5dc152 100644 --- a/dive.c +++ b/dive.c @@ -1665,13 +1665,8 @@ int gasmix_distance(const struct gasmix *a, const struct gasmix *b) * *mix = structure containing cylinder gas mixture information. * This function called by: calculate_gas_information_new() in profile.c; add_segment() in deco.c. */ -extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2, enum dive_comp_type divemode, int sac) +extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2, enum dive_comp_type divemode) { - if (!sac) { - /* The SAC has not yet been computer, so use the default * - * We might try harder... */ - sac = prefs.bottomsac; - } if (po2) { // This is probably a CCR dive where pressures->o2 is defined if (po2 >= amb_pressure) { pressures->o2 = amb_pressure; @@ -1687,14 +1682,14 @@ extern void fill_pressures(struct gas_pressures *pressures, const double amb_pre } } else { if (divemode == PSCR) { /* The steady state approximation should be good enough */ - pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure - (1.0 - get_o2(mix) / 1000.0) * prefs.o2consumption / (sac * prefs.pscr_ratio / 1000.0); + pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure - (1.0 - get_o2(mix) / 1000.0) * prefs.o2consumption / (prefs.bottomsac * prefs.pscr_ratio / 1000.0); pressures->he = (amb_pressure - pressures->o2) * get_he(mix) / (1000.0 - get_o2(mix)); pressures->n2 = (amb_pressure - pressures->o2) * (1000 - get_o2(mix) - get_he(mix)) / (1000.0 - get_o2(mix)); } else { - // Open circuit dives: no gas pressure values available, they need to be calculated - pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure; // These calculations are also used if the CCR calculation above.. - pressures->he = get_he(mix) / 1000.0 * amb_pressure; // ..returned a po2 of zero (i.e. o2 sensor data not resolvable) - pressures->n2 = (1000 - get_o2(mix) - get_he(mix)) / 1000.0 * amb_pressure; + // Open circuit dives: no gas pressure values available, they need to be calculated + pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure; // These calculations are also used if the CCR calculation above.. + pressures->he = get_he(mix) / 1000.0 * amb_pressure; // ..returned a po2 of zero (i.e. o2 sensor data not resolvable) + pressures->n2 = (1000 - get_o2(mix) - get_he(mix)) / 1000.0 * amb_pressure; } } } diff --git a/dive.h b/dive.h index 327598b..56f38f9 100644 --- a/dive.h +++ b/dive.h @@ -143,7 +143,7 @@ struct gas_pressures { double o2, n2, he; }; -extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2, enum dive_comp_type dctype, int sac); +extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2, enum dive_comp_type dctype); extern void sanitize_gasmix(struct gasmix *mix); extern int gasmix_distance(const struct gasmix *a, const struct gasmix *b); diff --git a/profile.c b/profile.c index 8246a96..c8f7811 100644 --- a/profile.c +++ b/profile.c @@ -946,7 +946,7 @@ static void calculate_gas_information_new(struct dive *dive, struct plot_info *p amb_pressure = depth_to_mbar(entry->depth, dive) / 1000.0; - fill_pressures(&entry->pressures, amb_pressure, &dive->cylinder[cylinderindex].gasmix, entry->o2pressure.mbar / 1000.0, dive->dc.divemode, entry->sac); + fill_pressures(&entry->pressures, amb_pressure, &dive->cylinder[cylinderindex].gasmix, entry->o2pressure.mbar / 1000.0, dive->dc.divemode); fn2 = (int)(1000.0 * entry->pressures.n2 / amb_pressure); fhe = (int)(1000.0 * entry->pressures.he / amb_pressure); -- 1.9.3 (Apple Git-50)