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344a429e48
I think that displaying tissue loadings either as pressure or as percentages is not very intuitive but that it makes much more sense when translated to ceiling depths. This change enables just that for the 16 tissues in our calculated ceiling and visualizes this in the profile graph. There is a checkbox in the preferences to turn this on. If enabled, all tissues having non-trivial ceilings are also shown in the info box. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
277 lines
10 KiB
C
277 lines
10 KiB
C
/* calculate deco values
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* based on Bühlmann ZHL-16b
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* based on an implemention by heinrichs weikamp for the DR5
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* the original file was given to Subsurface under the GPLv2
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* by Matthias Heinrichs
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*
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* The implementation below is a fairly complete rewrite since then
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* (C) Robert C. Helling 2013 and released under the GPLv2
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*
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* add_segment() - add <seconds> at the given pressure, breathing gasmix
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* deco_allowed_depth() - ceiling based on lead tissue, surface pressure, 3m increments or smooth
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* set_gf() - set Buehlmann gradient factors
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* clear_deco()
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* cache_deco_state()
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* restore_deco_state()
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* dump_tissues()
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*/
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#include <math.h>
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#include <string.h>
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#include "dive.h"
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//! Option structure for Buehlmann decompression.
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struct buehlmann_config {
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double satmult; //! safety at inert gas accumulation as percentage of effect (more than 100).
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double desatmult; //! safety at inert gas depletion as percentage of effect (less than 100).
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int last_deco_stop_in_mtr; //! depth of last_deco_stop.
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double gf_high; //! gradient factor high (at surface).
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double gf_low; //! gradient factor low (at bottom/start of deco calculation).
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double gf_low_position_min; //! gf_low_position below surface_min_shallow.
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};
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struct buehlmann_config buehlmann_config = { 1.0, 1.01, 0, 0.75, 0.35, 2.0 };
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const double buehlmann_N2_a[] = {1.1696, 1.0, 0.8618, 0.7562,
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0.62, 0.5043, 0.441, 0.4,
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0.375, 0.35, 0.3295, 0.3065,
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0.2835, 0.261, 0.248, 0.2327};
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const double buehlmann_N2_b[] = {0.5578, 0.6514, 0.7222, 0.7825,
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0.8126, 0.8434, 0.8693, 0.8910,
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0.9092, 0.9222, 0.9319, 0.9403,
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0.9477, 0.9544, 0.9602, 0.9653};
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const double buehlmann_N2_t_halflife[] = {5.0, 8.0, 12.5, 18.5,
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27.0, 38.3, 54.3, 77.0,
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109.0, 146.0, 187.0, 239.0,
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305.0, 390.0, 498.0, 635.0};
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const double buehlmann_N2_factor_expositon_one_second[] = {
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2.30782347297664E-003, 1.44301447809736E-003, 9.23769302935806E-004, 6.24261986779007E-004,
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4.27777107246730E-004, 3.01585140931371E-004, 2.12729727268379E-004, 1.50020603047807E-004,
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1.05980191127841E-004, 7.91232600646508E-005, 6.17759153688224E-005, 4.83354552742732E-005,
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3.78761777920511E-005, 2.96212356654113E-005, 2.31974277413727E-005, 1.81926738960225E-005};
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const double buehlmann_He_a[] = { 1.6189, 1.383 , 1.1919, 1.0458,
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0.922 , 0.8205, 0.7305, 0.6502,
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0.595 , 0.5545, 0.5333, 0.5189,
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0.5181, 0.5176, 0.5172, 0.5119};
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const double buehlmann_He_b[] = {0.4770, 0.5747, 0.6527, 0.7223,
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0.7582, 0.7957, 0.8279, 0.8553,
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0.8757, 0.8903, 0.8997, 0.9073,
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0.9122, 0.9171, 0.9217, 0.9267};
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const double buehlmann_He_t_halflife[] = {1.88, 3.02, 4.72, 6.99,
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10.21, 14.48, 20.53, 29.11,
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41.20, 55.19, 70.69, 90.34,
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115.29, 147.42, 188.24, 240.03};
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const double buehlmann_He_factor_expositon_one_second[] = {
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6.12608039419837E-003, 3.81800836683133E-003, 2.44456078654209E-003, 1.65134647076792E-003,
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1.13084424730725E-003, 7.97503165599123E-004, 5.62552521860549E-004, 3.96776399429366E-004,
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2.80360036664540E-004, 2.09299583354805E-004, 1.63410794820518E-004, 1.27869320250551E-004,
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1.00198406028040E-004, 7.83611475491108E-005, 6.13689891868496E-005, 4.81280465299827E-005};
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#define WV_PRESSURE 0.0627 // water vapor pressure in bar
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#define DECO_STOPS_MULTIPLIER_MM 3000.0
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#define GF_LOW_AT_MAXDEPTH 0
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double tissue_n2_sat[16];
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double tissue_he_sat[16];
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int ci_pointing_to_guiding_tissue;
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double gf_low_pressure_this_dive;
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#define TISSUE_ARRAY_SZ sizeof(tissue_n2_sat)
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double tolerated_by_tissue[16];
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static double tissue_tolerance_calc(const struct dive *dive)
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{
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int ci = -1;
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double tissue_inertgas_saturation, buehlmann_inertgas_a, buehlmann_inertgas_b;
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double ret_tolerance_limit_ambient_pressure = 0.0;
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double gf_high = buehlmann_config.gf_high;
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double gf_low = buehlmann_config.gf_low;
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double surface = get_surface_pressure_in_mbar(dive, TRUE) / 1000.0;
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double lowest_ceiling;
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for (ci = 0; ci < 16; ci++)
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{
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double tolerated;
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tissue_inertgas_saturation = tissue_n2_sat[ci] + tissue_he_sat[ci];
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buehlmann_inertgas_a = ((buehlmann_N2_a[ci] * tissue_n2_sat[ci]) + (buehlmann_He_a[ci] * tissue_he_sat[ci])) / tissue_inertgas_saturation;
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buehlmann_inertgas_b = ((buehlmann_N2_b[ci] * tissue_n2_sat[ci]) + (buehlmann_He_b[ci] * tissue_he_sat[ci])) / tissue_inertgas_saturation;
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/* tolerated = (tissue_inertgas_saturation - buehlmann_inertgas_a) * buehlmann_inertgas_b; */
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#if !GF_LOW_AT_MAXDEPTH
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lowest_ceiling = (buehlmann_inertgas_b * tissue_inertgas_saturation - gf_low * buehlmann_inertgas_a * buehlmann_inertgas_b) /
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((1.0 - buehlmann_inertgas_b) * gf_low + buehlmann_inertgas_b);
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if (lowest_ceiling > gf_low_pressure_this_dive)
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gf_low_pressure_this_dive = lowest_ceiling;
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#endif
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tolerated = (-buehlmann_inertgas_a * buehlmann_inertgas_b * (gf_high * gf_low_pressure_this_dive - gf_low * surface) -
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(1.0 - buehlmann_inertgas_b) * (gf_high - gf_low) * gf_low_pressure_this_dive * surface +
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buehlmann_inertgas_b * (gf_low_pressure_this_dive - surface) * tissue_inertgas_saturation) /
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(-buehlmann_inertgas_a * buehlmann_inertgas_b * (gf_high - gf_low) +
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(1.0 - buehlmann_inertgas_b)*(gf_low * gf_low_pressure_this_dive - gf_high * surface) +
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buehlmann_inertgas_b * (gf_low_pressure_this_dive - surface));
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tolerated_by_tissue[ci] = tolerated;
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if (tolerated > ret_tolerance_limit_ambient_pressure)
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{
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ci_pointing_to_guiding_tissue = ci;
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ret_tolerance_limit_ambient_pressure = tolerated;
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}
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}
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return ret_tolerance_limit_ambient_pressure;
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}
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/* add period_in_seconds at the given pressure and gas to the deco calculation */
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double add_segment(double pressure, const struct gasmix *gasmix, int period_in_seconds, int ccpo2, const struct dive *dive)
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{
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int ci;
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int fo2 = get_o2(gasmix), fhe = get_he(gasmix);
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double ppn2 = (pressure - WV_PRESSURE) * (1000 - fo2 - fhe) / 1000.0;
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double pphe = (pressure - WV_PRESSURE) * fhe / 1000.0;
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#if GF_LOW_AT_MAXDEPTH
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if (pressure > gf_low_pressure_this_dive)
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gf_low_pressure_this_dive = pressure;
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#endif
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if (ccpo2) { /* CC */
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double rel_o2_amb, f_dilutent;
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rel_o2_amb = ccpo2 / pressure / 1000;
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f_dilutent = (1 - rel_o2_amb) / (1 - fo2 / 1000.0);
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if (f_dilutent < 0) { /* setpoint is higher than ambient pressure -> pure O2 */
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ppn2 = 0.0;
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pphe = 0.0;
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} else if (f_dilutent < 1.0) {
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ppn2 *= f_dilutent;
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pphe *= f_dilutent;
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}
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}
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if (period_in_seconds == 1) { /* one second interval during dive */
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for (ci = 0; ci < 16; ci++) {
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if (ppn2 - tissue_n2_sat[ci] > 0)
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tissue_n2_sat[ci] += buehlmann_config.satmult * (ppn2 - tissue_n2_sat[ci]) *
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buehlmann_N2_factor_expositon_one_second[ci];
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else
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tissue_n2_sat[ci] += buehlmann_config.desatmult * (ppn2 - tissue_n2_sat[ci]) *
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buehlmann_N2_factor_expositon_one_second[ci];
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if (pphe - tissue_he_sat[ci] > 0)
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tissue_he_sat[ci] += buehlmann_config.satmult * (pphe - tissue_he_sat[ci]) *
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buehlmann_He_factor_expositon_one_second[ci];
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else
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tissue_he_sat[ci] += buehlmann_config.desatmult * (pphe - tissue_he_sat[ci]) *
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buehlmann_He_factor_expositon_one_second[ci];
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}
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} else { /* all other durations */
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for (ci = 0; ci < 16; ci++)
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{
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if (ppn2 - tissue_n2_sat[ci] > 0)
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tissue_n2_sat[ci] += buehlmann_config.satmult * (ppn2 - tissue_n2_sat[ci]) *
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(1 - pow(2.0,(- period_in_seconds / (buehlmann_N2_t_halflife[ci] * 60))));
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else
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tissue_n2_sat[ci] += buehlmann_config.desatmult * (ppn2 - tissue_n2_sat[ci]) *
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(1 - pow(2.0,(- period_in_seconds / (buehlmann_N2_t_halflife[ci] * 60))));
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if (pphe - tissue_he_sat[ci] > 0)
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tissue_he_sat[ci] += buehlmann_config.satmult * (pphe - tissue_he_sat[ci]) *
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(1 - pow(2.0,(- period_in_seconds / (buehlmann_He_t_halflife[ci] * 60))));
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else
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tissue_he_sat[ci] += buehlmann_config.desatmult * (pphe - tissue_he_sat[ci]) *
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(1 - pow(2.0,(- period_in_seconds / (buehlmann_He_t_halflife[ci] * 60))));
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}
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}
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return tissue_tolerance_calc(dive);
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}
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void dump_tissues()
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{
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int ci;
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printf("N2 tissues:");
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for (ci = 0; ci < 16; ci++)
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printf(" %6.3e", tissue_n2_sat[ci]);
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printf("\nHe tissues:");
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for (ci = 0; ci < 16; ci++)
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printf(" %6.3e", tissue_he_sat[ci]);
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printf("\n");
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}
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void clear_deco(double surface_pressure)
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{
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int ci;
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for (ci = 0; ci < 16; ci++) {
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tissue_n2_sat[ci] = (surface_pressure - WV_PRESSURE) * N2_IN_AIR / 1000;
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tissue_he_sat[ci] = 0.0;
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}
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gf_low_pressure_this_dive = surface_pressure + buehlmann_config.gf_low_position_min;
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}
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void cache_deco_state(double tissue_tolerance, char **cached_datap)
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{
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char *data = *cached_datap;
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if (!data) {
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data = malloc(2 * TISSUE_ARRAY_SZ + 2 * sizeof(double) + sizeof(int));
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*cached_datap = data;
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}
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memcpy(data, tissue_n2_sat, TISSUE_ARRAY_SZ);
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data += TISSUE_ARRAY_SZ;
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memcpy(data, tissue_he_sat, TISSUE_ARRAY_SZ);
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data += TISSUE_ARRAY_SZ;
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memcpy(data, &gf_low_pressure_this_dive, sizeof(double));
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data += sizeof(double);
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memcpy(data, &tissue_tolerance, sizeof(double));
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data += sizeof(double);
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memcpy(data, &ci_pointing_to_guiding_tissue, sizeof(int));
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}
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double restore_deco_state(char *data)
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{
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double tissue_tolerance;
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memcpy(tissue_n2_sat, data, TISSUE_ARRAY_SZ);
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data += TISSUE_ARRAY_SZ;
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memcpy(tissue_he_sat, data, TISSUE_ARRAY_SZ);
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data += TISSUE_ARRAY_SZ;
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memcpy(&gf_low_pressure_this_dive, data, sizeof(double));
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data += sizeof(double);
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memcpy(&tissue_tolerance, data, sizeof(double));
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data += sizeof(double);
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memcpy(&ci_pointing_to_guiding_tissue, data, sizeof(int));
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return tissue_tolerance;
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}
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unsigned int deco_allowed_depth(double tissues_tolerance, double surface_pressure, struct dive *dive, gboolean smooth)
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{
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unsigned int depth;
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double pressure_delta;
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/* Avoid negative depths */
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pressure_delta = tissues_tolerance > surface_pressure ? tissues_tolerance - surface_pressure : 0.0;
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depth = rel_mbar_to_depth(pressure_delta * 1000, dive);
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if (!smooth)
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depth = ceil(depth / DECO_STOPS_MULTIPLIER_MM) * DECO_STOPS_MULTIPLIER_MM;
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if (depth > 0 && depth < buehlmann_config.last_deco_stop_in_mtr * 1000)
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depth = buehlmann_config.last_deco_stop_in_mtr * 1000;
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return depth;
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}
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void set_gf(short gflow, short gfhigh)
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{
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if (gflow != -1)
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buehlmann_config.gf_low = (double)gflow / 100.0;
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if (gfhigh != -1)
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buehlmann_config.gf_high = (double)gfhigh / 100.0;
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}
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