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Diffstat (limited to 'core/deco.c')
| -rw-r--r-- | core/deco.c | 601 |
1 files changed, 601 insertions, 0 deletions
diff --git a/core/deco.c b/core/deco.c new file mode 100644 index 000000000..af3e06126 --- /dev/null +++ b/core/deco.c @@ -0,0 +1,601 @@ +/* calculate deco values + * based on Bühlmann ZHL-16b + * based on an implemention by heinrichs weikamp for the DR5 + * the original file was given to Subsurface under the GPLv2 + * by Matthias Heinrichs + * + * The implementation below is a fairly complete rewrite since then + * (C) Robert C. Helling 2013 and released under the GPLv2 + * + * add_segment() - add <seconds> at the given pressure, breathing gasmix + * deco_allowed_depth() - ceiling based on lead tissue, surface pressure, 3m increments or smooth + * set_gf() - set Buehlmann gradient factors + * clear_deco() + * cache_deco_state() + * restore_deco_state() + * dump_tissues() + */ +#include <math.h> +#include <string.h> +#include "dive.h" +#include <assert.h> +#include "core/planner.h" + +#define cube(x) (x * x * x) + +// Subsurface appears to produce marginally less conservative plans than our benchmarks +// Introduce 1.2% additional conservatism +#define subsurface_conservatism_factor 1.012 + + +extern bool in_planner(); + +extern pressure_t first_ceiling_pressure; + +//! Option structure for Buehlmann decompression. +struct buehlmann_config { + double satmult; //! safety at inert gas accumulation as percentage of effect (more than 100). + double desatmult; //! safety at inert gas depletion as percentage of effect (less than 100). + int last_deco_stop_in_mtr; //! depth of last_deco_stop. + double gf_high; //! gradient factor high (at surface). + double gf_low; //! gradient factor low (at bottom/start of deco calculation). + double gf_low_position_min; //! gf_low_position below surface_min_shallow. + bool gf_low_at_maxdepth; //! if true, gf_low applies at max depth instead of at deepest ceiling. +}; + +struct buehlmann_config buehlmann_config = { + .satmult = 1.0, + .desatmult = 1.01, + .last_deco_stop_in_mtr = 0, + .gf_high = 0.75, + .gf_low = 0.35, + .gf_low_position_min = 1.0, + .gf_low_at_maxdepth = false +}; + +//! Option structure for VPM-B decompression. +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 gradient_of_imperm; //! Gradient after which bubbles become impermeable (bar). + double surface_tension_gamma; //! Nucleons surface tension constant (N / bar = m2). + double skin_compression_gammaC; //! Skin compression gammaC (N / bar = m2). + 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 = { + .crit_radius_N2 = 0.55, + .crit_radius_He = 0.45, + .crit_volume_lambda = 199.58, + .gradient_of_imperm = 8.30865, // = 8.2 atm + .surface_tension_gamma = 0.18137175, // = 0.0179 N/msw + .skin_compression_gammaC = 2.6040525, // = 0.257 N/msw + .regeneration_time = 20160.0, + .other_gases_pressure = 0.1359888 +}; + +const double buehlmann_N2_a[] = { 1.1696, 1.0, 0.8618, 0.7562, + 0.62, 0.5043, 0.441, 0.4, + 0.375, 0.35, 0.3295, 0.3065, + 0.2835, 0.261, 0.248, 0.2327 }; + +const double buehlmann_N2_b[] = { 0.5578, 0.6514, 0.7222, 0.7825, + 0.8126, 0.8434, 0.8693, 0.8910, + 0.9092, 0.9222, 0.9319, 0.9403, + 0.9477, 0.9544, 0.9602, 0.9653 }; + +const double buehlmann_N2_t_halflife[] = { 5.0, 8.0, 12.5, 18.5, + 27.0, 38.3, 54.3, 77.0, + 109.0, 146.0, 187.0, 239.0, + 305.0, 390.0, 498.0, 635.0 }; + +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, + 1.05980191127841E-004, 7.91232600646508E-005, 6.17759153688224E-005, 4.83354552742732E-005, + 3.78761777920511E-005, 2.96212356654113E-005, 2.31974277413727E-005, 1.81926738960225E-005 +}; + +const double buehlmann_He_a[] = { 1.6189, 1.383, 1.1919, 1.0458, + 0.922, 0.8205, 0.7305, 0.6502, + 0.595, 0.5545, 0.5333, 0.5189, + 0.5181, 0.5176, 0.5172, 0.5119 }; + +const double buehlmann_He_b[] = { 0.4770, 0.5747, 0.6527, 0.7223, + 0.7582, 0.7957, 0.8279, 0.8553, + 0.8757, 0.8903, 0.8997, 0.9073, + 0.9122, 0.9171, 0.9217, 0.9267 }; + +const double buehlmann_He_t_halflife[] = { 1.88, 3.02, 4.72, 6.99, + 10.21, 14.48, 20.53, 29.11, + 41.20, 55.19, 70.69, 90.34, + 115.29, 147.42, 188.24, 240.03 }; + +const double buehlmann_He_factor_expositon_one_second[] = { + 6.12608039419837E-003, 3.81800836683133E-003, 2.44456078654209E-003, 1.65134647076792E-003, + 1.13084424730725E-003, 7.97503165599123E-004, 5.62552521860549E-004, 3.96776399429366E-004, + 2.80360036664540E-004, 2.09299583354805E-004, 1.63410794820518E-004, 1.27869320250551E-004, + 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 }; + +/* Inspired gas loading equations depend on the partial pressure of inert gas in the alveolar. + * P_alv = (P_amb - P_H2O + (1 - Rq) / Rq * P_CO2) * f + * where: + * P_alv alveolar partial pressure of inert gas + * P_amb ambient pressure + * P_H2O water vapour partial pressure = ~0.0627 bar + * P_CO2 carbon dioxide partial pressure = ~0.0534 bar + * Rq respiratory quotient (O2 consumption / CO2 production) + * f fraction of inert gas + * + * In our calculations, we simplify this to use an effective water vapour pressure + * WV = P_H20 - (1 - Rq) / Rq * P_CO2 + * + * Buhlmann ignored the contribution of CO2 (i.e. Rq = 1.0), whereas Schreiner adopted Rq = 0.8. + * WV_Buhlmann = PP_H2O = 0.0627 bar + * WV_Schreiner = 0.0627 - (1 - 0.8) / Rq * 0.0534 = 0.0493 bar + + * Buhlmann calculations use the Buhlmann value, VPM-B calculations use the Schreiner value. +*/ +#define WV_PRESSURE 0.0627 // water vapor pressure in bar, based on respiratory quotient Rq = 1.0 (Buhlmann value) +#define WV_PRESSURE_SCHREINER 0.0493 // water vapor pressure in bar, based on respiratory quotient Rq = 0.8 (Schreiner value) + +#define DECO_STOPS_MULTIPLIER_MM 3000.0 +#define NITROGEN_FRACTION 0.79 + +double tissue_n2_sat[16]; +double tissue_he_sat[16]; +int ci_pointing_to_guiding_tissue; +double gf_low_pressure_this_dive; +#define TISSUE_ARRAY_SZ sizeof(tissue_n2_sat) + +double tolerated_by_tissue[16]; +double tissue_inertgas_saturation[16]; +double buehlmann_inertgas_a[16], buehlmann_inertgas_b[16]; + +double max_n2_crushing_pressure[16]; +double max_he_crushing_pressure[16]; + +double crushing_onset_tension[16]; // total inert gas tension in the t* moment +double n2_regen_radius[16]; // rs +double he_regen_radius[16]; +double max_ambient_pressure; // last moment we were descending + +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] * subsurface_conservatism_factor; + 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] * subsurface_conservatism_factor; + return vpmb_config.crit_radius_N2; +} + +// Solve another cubic equation, this time +// x^3 - B x - C == 0 +// Use trigonometric formula for negative discriminants (see Wikipedia for details) + +double solve_cubic2(double B, double C) +{ + double discriminant = 27 * C * C - 4 * cube(B); + if (discriminant < 0.0) { + return 2.0 * sqrt(B / 3.0) * cos(acos(3.0 * C * sqrt(3.0 / B) / (2.0 * B)) / 3.0); + } + + double denominator = pow(9 * C + sqrt(3 * discriminant), 1 / 3.0); + + return pow(2.0 / 3.0, 1.0 / 3.0) * B / denominator + denominator / pow(18.0, 1.0 / 3.0); +} + +// This is a simplified formula avoiding radii. It uses the fact that Boyle's law says +// pV = (G + P_amb) / G^3 is constant to solve for the new gradient G. + +double update_gradient(double next_stop_pressure, double first_gradient) +{ + double B = cube(first_gradient) / (first_ceiling_pressure.mbar / 1000.0 + first_gradient); + double C = next_stop_pressure * B; + + double new_gradient = solve_cubic2(B, C); + + if (new_gradient < 0.0) + report_error("Negative gradient encountered!"); + return new_gradient; +} + +double vpmb_tolerated_ambient_pressure(double reference_pressure, int ci) +{ + double n2_gradient, he_gradient, total_gradient; + + if (reference_pressure >= first_ceiling_pressure.mbar / 1000.0 || !first_ceiling_pressure.mbar) { + n2_gradient = bottom_n2_gradient[ci]; + he_gradient = bottom_he_gradient[ci]; + } else { + n2_gradient = update_gradient(reference_pressure, bottom_n2_gradient[ci]); + he_gradient = update_gradient(reference_pressure, bottom_he_gradient[ci]); + } + + total_gradient = ((n2_gradient * tissue_n2_sat[ci]) + (he_gradient * tissue_he_sat[ci])) / (tissue_n2_sat[ci] + tissue_he_sat[ci]); + + return tissue_n2_sat[ci] + tissue_he_sat[ci] + vpmb_config.other_gases_pressure - total_gradient; +} + + +double tissue_tolerance_calc(const struct dive *dive, double pressure) +{ + int ci = -1; + double ret_tolerance_limit_ambient_pressure = 0.0; + double gf_high = buehlmann_config.gf_high; + double gf_low = buehlmann_config.gf_low; + double surface = get_surface_pressure_in_mbar(dive, true) / 1000.0; + double lowest_ceiling = 0.0; + double tissue_lowest_ceiling[16]; + + if (prefs.deco_mode != VPMB) { + for (ci = 0; ci < 16; ci++) { + tissue_inertgas_saturation[ci] = tissue_n2_sat[ci] + tissue_he_sat[ci]; + buehlmann_inertgas_a[ci] = ((buehlmann_N2_a[ci] * tissue_n2_sat[ci]) + (buehlmann_He_a[ci] * tissue_he_sat[ci])) / tissue_inertgas_saturation[ci]; + buehlmann_inertgas_b[ci] = ((buehlmann_N2_b[ci] * tissue_n2_sat[ci]) + (buehlmann_He_b[ci] * tissue_he_sat[ci])) / tissue_inertgas_saturation[ci]; + + + /* tolerated = (tissue_inertgas_saturation - buehlmann_inertgas_a) * buehlmann_inertgas_b; */ + + tissue_lowest_ceiling[ci] = (buehlmann_inertgas_b[ci] * tissue_inertgas_saturation[ci] - gf_low * buehlmann_inertgas_a[ci] * buehlmann_inertgas_b[ci]) / + ((1.0 - buehlmann_inertgas_b[ci]) * gf_low + buehlmann_inertgas_b[ci]); + if (tissue_lowest_ceiling[ci] > lowest_ceiling) + lowest_ceiling = tissue_lowest_ceiling[ci]; + if (!buehlmann_config.gf_low_at_maxdepth) { + if (lowest_ceiling > gf_low_pressure_this_dive) + gf_low_pressure_this_dive = lowest_ceiling; + } + } + for (ci = 0; ci < 16; ci++) { + double tolerated; + + if ((surface / buehlmann_inertgas_b[ci] + buehlmann_inertgas_a[ci] - surface) * gf_high + surface < + (gf_low_pressure_this_dive / buehlmann_inertgas_b[ci] + buehlmann_inertgas_a[ci] - gf_low_pressure_this_dive) * gf_low + gf_low_pressure_this_dive) + tolerated = (-buehlmann_inertgas_a[ci] * buehlmann_inertgas_b[ci] * (gf_high * gf_low_pressure_this_dive - gf_low * surface) - + (1.0 - buehlmann_inertgas_b[ci]) * (gf_high - gf_low) * gf_low_pressure_this_dive * surface + + buehlmann_inertgas_b[ci] * (gf_low_pressure_this_dive - surface) * tissue_inertgas_saturation[ci]) / + (-buehlmann_inertgas_a[ci] * buehlmann_inertgas_b[ci] * (gf_high - gf_low) + + (1.0 - buehlmann_inertgas_b[ci]) * (gf_low * gf_low_pressure_this_dive - gf_high * surface) + + buehlmann_inertgas_b[ci] * (gf_low_pressure_this_dive - surface)); + else + tolerated = ret_tolerance_limit_ambient_pressure; + + + tolerated_by_tissue[ci] = tolerated; + + if (tolerated >= ret_tolerance_limit_ambient_pressure) { + ci_pointing_to_guiding_tissue = ci; + ret_tolerance_limit_ambient_pressure = tolerated; + } + } + } else { + // VPM-B ceiling + double reference_pressure; + + ret_tolerance_limit_ambient_pressure = pressure; + // The Boyle compensated gradient depends on ambient pressure. For the ceiling, this should set the ambient pressure. + do { + reference_pressure = ret_tolerance_limit_ambient_pressure; + ret_tolerance_limit_ambient_pressure = 0.0; + for (ci = 0; ci < 16; ci++) { + double tolerated = vpmb_tolerated_ambient_pressure(reference_pressure, ci); + if (tolerated >= ret_tolerance_limit_ambient_pressure) { + ci_pointing_to_guiding_tissue = ci; + ret_tolerance_limit_ambient_pressure = tolerated; + } + tolerated_by_tissue[ci] = tolerated; + } + // We are doing ok if the gradient was computed within ten centimeters of the ceiling. + } while (fabs(ret_tolerance_limit_ambient_pressure - reference_pressure) > 0.01); + } + return ret_tolerance_limit_ambient_pressure; +} + +/* + * Return buelman factor for a particular period and tissue index. + * + * We cache the last factor, since we commonly call this with the + * same values... We have a special "fixed cache" for the one second + * case, although I wonder if that's even worth it considering the + * more general-purpose cache. + */ +struct factor_cache { + int last_period; + double last_factor; +}; + +double n2_factor(int period_in_seconds, int ci) +{ + static struct factor_cache cache[16]; + + if (period_in_seconds == 1) + return buehlmann_N2_factor_expositon_one_second[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)); + } + + return cache[ci].last_factor; +} + +double he_factor(int period_in_seconds, int ci) +{ + static struct factor_cache cache[16]; + + if (period_in_seconds == 1) + return buehlmann_He_factor_expositon_one_second[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)); + } + + 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 - ((in_planner() && (prefs.deco_mode == VPMB)) ? WV_PRESSURE_SCHREINER : 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; +} + +void vpmb_start_gradient() +{ + int ci; + + for (ci = 0; ci < 16; ++ci) { + initial_n2_gradient[ci] = bottom_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] = 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]); + } +} + +void vpmb_next_gradient(double deco_time, double surface_pressure) +{ + int ci; + double n2_b, n2_c; + double he_b, he_c; + double desat_time; + deco_time /= 60.0; + + for (ci = 0; ci < 16; ++ci) { + 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 * 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 * desat_time); + + bottom_n2_gradient[ci] = 0.5 * ( n2_b + sqrt(n2_b * n2_b - 4.0 * n2_c)); + bottom_he_gradient[ci] = 0.5 * ( he_b + sqrt(he_b * he_b - 4.0 * he_c)); + } +} + +// A*r^3 - B*r^2 - C == 0 +// Solved with the help of mathematica + +double solve_cubic(double A, double B, double C) +{ + double BA = B/A; + double CA = C/A; + + double discriminant = CA * (4 * cube(BA) + 27 * CA); + + // Let's make sure we have a real solution: + if (discriminant < 0.0) { + // This should better not happen + report_error("Complex solution for inner pressure encountered!\n A=%f\tB=%f\tC=%f\n", A, B, C); + return 0.0; + } + double denominator = pow(cube(BA) + 1.5 * (9 * CA + sqrt(3.0) * sqrt(discriminant)), 1/3.0); + return (BA + BA * BA / denominator + denominator) / 3.0; + +} + + +void nuclear_regeneration(double time) +{ + time /= 60.0; + int ci; + 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 / 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 + (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)); + } +} + + +// Calculates the nucleons inner pressure during the impermeable period +double calc_inner_pressure(double crit_radius, double onset_tension, double current_ambient_pressure) +{ + double onset_radius = 1.0 / (vpmb_config.gradient_of_imperm / (2.0 * (vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma)) + 1.0 / crit_radius); + + + double A = current_ambient_pressure - vpmb_config.gradient_of_imperm + (2.0 * (vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma)) / onset_radius; + double B = 2.0 * (vpmb_config.skin_compression_gammaC - vpmb_config.surface_tension_gamma); + double C = onset_tension * pow(onset_radius, 3); + + double current_radius = solve_cubic(A, B, C); + + return onset_tension * onset_radius * onset_radius * onset_radius / (current_radius * current_radius * current_radius); +} + +// Calculates the crushing pressure in the given moment. Updates crushing_onset_tension and critical radius if needed +void calc_crushing_pressure(double pressure) +{ + int ci; + double gradient; + double gas_tension; + double n2_crushing_pressure, he_crushing_pressure; + double n2_inner_pressure, he_inner_pressure; + + for (ci = 0; ci < 16; ++ci) { + gas_tension = tissue_n2_sat[ci] + tissue_he_sat[ci] + vpmb_config.other_gases_pressure; + gradient = pressure - gas_tension; + + if (gradient <= vpmb_config.gradient_of_imperm) { // permeable situation + n2_crushing_pressure = he_crushing_pressure = gradient; + crushing_onset_tension[ci] = gas_tension; + } + else { // impermeable + if (max_ambient_pressure >= pressure) + return; + + 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; + } + max_n2_crushing_pressure[ci] = MAX(max_n2_crushing_pressure[ci], n2_crushing_pressure); + max_he_crushing_pressure[ci] = MAX(max_he_crushing_pressure[ci], he_crushing_pressure); + } + max_ambient_pressure = MAX(pressure, max_ambient_pressure); +} + +/* add period_in_seconds at the given pressure and gas to the deco calculation */ +void add_segment(double pressure, const struct gasmix *gasmix, int period_in_seconds, int ccpo2, const struct dive *dive, int sac) +{ + (void) sac; + int ci; + struct gas_pressures pressures; + + fill_pressures(&pressures, pressure - ((in_planner() && (prefs.deco_mode == VPMB)) ? WV_PRESSURE_SCHREINER : 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; + + for (ci = 0; ci < 16; ci++) { + double pn2_oversat = pressures.n2 - tissue_n2_sat[ci]; + double phe_oversat = pressures.he - tissue_he_sat[ci]; + double n2_f = n2_factor(period_in_seconds, ci); + double he_f = he_factor(period_in_seconds, ci); + double n2_satmult = pn2_oversat > 0 ? buehlmann_config.satmult : buehlmann_config.desatmult; + double he_satmult = phe_oversat > 0 ? buehlmann_config.satmult : buehlmann_config.desatmult; + + tissue_n2_sat[ci] += n2_satmult * pn2_oversat * n2_f; + tissue_he_sat[ci] += he_satmult * phe_oversat * he_f; + } + if(prefs.deco_mode == VPMB) + calc_crushing_pressure(pressure); + return; +} + +void dump_tissues() +{ + int ci; + printf("N2 tissues:"); + for (ci = 0; ci < 16; ci++) + printf(" %6.3e", tissue_n2_sat[ci]); + printf("\nHe tissues:"); + for (ci = 0; ci < 16; ci++) + printf(" %6.3e", tissue_he_sat[ci]); + printf("\n"); +} + +void clear_deco(double surface_pressure) +{ + int ci; + for (ci = 0; ci < 16; ci++) { + tissue_n2_sat[ci] = (surface_pressure - ((in_planner() && (prefs.deco_mode == VPMB)) ? WV_PRESSURE_SCHREINER : WV_PRESSURE)) * N2_IN_AIR / 1000; + tissue_he_sat[ci] = 0.0; + max_n2_crushing_pressure[ci] = 0.0; + max_he_crushing_pressure[ci] = 0.0; + n2_regen_radius[ci] = get_crit_radius_N2(); + he_regen_radius[ci] = get_crit_radius_He(); + } + gf_low_pressure_this_dive = surface_pressure; + if (!buehlmann_config.gf_low_at_maxdepth) + gf_low_pressure_this_dive += buehlmann_config.gf_low_position_min; + max_ambient_pressure = 0.0; +} + +void cache_deco_state(char **cached_datap) +{ + char *data = *cached_datap; + + if (!data) { + data = malloc(2 * TISSUE_ARRAY_SZ + sizeof(double) + sizeof(int)); + *cached_datap = data; + } + memcpy(data, tissue_n2_sat, TISSUE_ARRAY_SZ); + data += TISSUE_ARRAY_SZ; + memcpy(data, tissue_he_sat, TISSUE_ARRAY_SZ); + data += TISSUE_ARRAY_SZ; + memcpy(data, &gf_low_pressure_this_dive, sizeof(double)); + data += sizeof(double); + memcpy(data, &ci_pointing_to_guiding_tissue, sizeof(int)); +} + +void restore_deco_state(char *data) +{ + memcpy(tissue_n2_sat, data, TISSUE_ARRAY_SZ); + data += TISSUE_ARRAY_SZ; + memcpy(tissue_he_sat, data, TISSUE_ARRAY_SZ); + data += TISSUE_ARRAY_SZ; + memcpy(&gf_low_pressure_this_dive, data, sizeof(double)); + data += sizeof(double); + memcpy(&ci_pointing_to_guiding_tissue, data, sizeof(int)); +} + +int deco_allowed_depth(double tissues_tolerance, double surface_pressure, struct dive *dive, bool smooth) +{ + int depth; + double pressure_delta; + + /* Avoid negative depths */ + pressure_delta = tissues_tolerance > surface_pressure ? tissues_tolerance - surface_pressure : 0.0; + + depth = rel_mbar_to_depth(pressure_delta * 1000, dive); + + if (!smooth) + depth = ceil(depth / DECO_STOPS_MULTIPLIER_MM) * DECO_STOPS_MULTIPLIER_MM; + + if (depth > 0 && depth < buehlmann_config.last_deco_stop_in_mtr * 1000) + depth = buehlmann_config.last_deco_stop_in_mtr * 1000; + + return depth; +} + +void set_gf(short gflow, short gfhigh, bool gf_low_at_maxdepth) +{ + if (gflow != -1) + buehlmann_config.gf_low = (double)gflow / 100.0; + if (gfhigh != -1) + buehlmann_config.gf_high = (double)gfhigh / 100.0; + buehlmann_config.gf_low_at_maxdepth = gf_low_at_maxdepth; +} |