diff options
| -rw-r--r-- | deco.c | 127 |
1 files changed, 24 insertions, 103 deletions
@@ -1,18 +1,19 @@ /* calculate deco values * based on Bühlmann ZHL-16b * based on an implemention by heinrichs weikamp for the DR5 - * the original file doesn't carry a license and is used here with - * the permission of Matthias Heinrichs + * the original file was given to Subsurface under the GPLv2 + * by Matthias Heinrichs * - * The implementation below is (C) Dirk Hohndel 2012 and released under the GPLv2 + * The implementation below is a fairly complete rewrite since then + * (C) Robert C. Helling 2013 and released under the GPLv2 * - * clear_deco() - call to initialize for a new deco calculation - * add_segment(pressure, gasmix, seconds) - add <seconds> at the given pressure, breathing gasmix - * deco_allowed_depth(tissues_tolerance, surface_pressure, dive, smooth) - * - ceiling based on lead tissue, surface pressure, 3m increments or smooth - * set_gf(gflow, gfhigh) - set Buehlmann gradient factors - * void cache_deco_state(tissue_tolerance, char **datap) - cache the relevant data allocate memory if needed - * double restore_deco_state(char *data) - restore the state and return the tissue_tolerance + * 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> @@ -22,16 +23,12 @@ 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). - double safety_dist_deco_stop;//! assumed distance to official decompression where decompression takes places. 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. - double gf_low_position_max; //! gf_low_position below surface_max_depth. - double gf_high_emergency; //! emergency gf factors - double gf_low_emergency; //! gradient factor low (at bottom/start of deco calculation). }; -struct buehlmann_config buehlmann_config = { 1.0, 1.01, 0.5, 0, 0.75, 0.35, 3.0, 6.0, 0.95, 0.95 }; +struct buehlmann_config buehlmann_config = { 1.0, 1.01, 3, 0.75, 0.35, 2.0 }; struct dive_data { double pressure; //! pesent ambient pressure double surface; //! pressure at water surface @@ -82,10 +79,6 @@ const double buehlmann_He_factor_expositon_one_second[] = { #define WV_PRESSURE 0.0627 /* water vapor pressure */ #define N2_IN_AIR 0.7902 -#define DIST_FROM_3_MTR 0.28 -#define PRESSURE_CHANGE_3M 0.3 -#define TOLERANCE 0.02 - #define DECO_STOPS_MULTIPLIER_MM 3000.0 double tissue_n2_sat[16]; @@ -95,38 +88,6 @@ int ci_pointing_to_guiding_tissue; double gf_low_pressure_this_dive; #define TISSUE_ARRAY_SZ sizeof(tissue_n2_sat) -/* static double actual_gradient_limit_obsolete(const struct dive_data *data) */ -/* { */ -/* double pressure_diff, limit_at_position; */ -/* double gf_high = buehlmann_config.gf_high; */ -/* double gf_low = buehlmann_config.gf_low; */ - -/* pressure_diff = data->pressure - data->surface; */ - -/* if (pressure_diff > TOLERANCE) { */ -/* if (pressure_diff < gf_low_position_this_dive) */ -/* limit_at_position = gf_high - ((gf_high - gf_low) * pressure_diff / gf_low_position_this_dive); */ -/* else */ -/* limit_at_position = gf_low; */ -/* } else { */ -/* limit_at_position = gf_high; */ -/* } */ -/* return limit_at_position; */ -/* } */ - -/* static double gradient_factor_calculation_obsolete(const struct dive_data *data) */ -/* { */ -/* double tissue_inertgas_saturation; */ - -/* tissue_inertgas_saturation = tissue_n2_sat[ci_pointing_to_guiding_tissue] + */ -/* tissue_he_sat[ci_pointing_to_guiding_tissue]; */ -/* if (tissue_inertgas_saturation < data->pressure) */ -/* return 0.0; */ -/* else */ -/* return (tissue_inertgas_saturation - data->pressure) / */ -/* (tissue_inertgas_saturation - tissue_tolerated_ambient_pressure[ci_pointing_to_guiding_tissue]); */ -/* } */ - static double tissue_tolerance_calc(const struct dive *dive) { int ci = -1; @@ -144,13 +105,12 @@ static double tissue_tolerance_calc(const struct dive *dive) /* tissue_tolerated_ambient_pressure[ci] = (tissue_inertgas_saturation - buehlmann_inertgas_a) * buehlmann_inertgas_b; */ - tissue_tolerated_ambient_pressure[ci] = (-buehlmann_inertgas_a * buehlmann_inertgas_b * (gf_high * gf_low_pressure_this_dive - gf_low * surface) - - (1.0 - buehlmann_inertgas_b) * (gf_high - gf_low) * gf_low_pressure_this_dive * surface - + buehlmann_inertgas_b * (gf_low_pressure_this_dive - surface) * tissue_inertgas_saturation) - / - (-buehlmann_inertgas_a * buehlmann_inertgas_b * (gf_high - gf_low) - + (1.0 - buehlmann_inertgas_b)*(gf_low * gf_low_pressure_this_dive - gf_high * surface) - + buehlmann_inertgas_b * (gf_low_pressure_this_dive - surface)); + tissue_tolerated_ambient_pressure[ci] = (-buehlmann_inertgas_a * buehlmann_inertgas_b * (gf_high * gf_low_pressure_this_dive - gf_low * surface) - + (1.0 - buehlmann_inertgas_b) * (gf_high - gf_low) * gf_low_pressure_this_dive * surface + + buehlmann_inertgas_b * (gf_low_pressure_this_dive - surface) * tissue_inertgas_saturation) / + (-buehlmann_inertgas_a * buehlmann_inertgas_b * (gf_high - gf_low) + + (1.0 - buehlmann_inertgas_b)*(gf_low * gf_low_pressure_this_dive - gf_high * surface) + + buehlmann_inertgas_b * (gf_low_pressure_this_dive - surface)); if (tissue_tolerated_ambient_pressure[ci] > ret_tolerance_limit_ambient_pressure) { @@ -161,7 +121,7 @@ static double tissue_tolerance_calc(const struct dive *dive) return ret_tolerance_limit_ambient_pressure; } -/* add a second at the given pressure and gas to the deco calculation */ +/* add period_in_seconds at the given pressure and gas to the deco calculation */ double add_segment(double pressure, struct gasmix *gasmix, int period_in_seconds, double ccpo2, const struct dive *dive) { int ci; @@ -239,7 +199,7 @@ void clear_deco(double surface_pressure) tissue_he_sat[ci] = 0.0; tissue_tolerated_ambient_pressure[ci] = 0.0; } - gf_low_pressure_this_dive = surface_pressure+ buehlmann_config.gf_low_position_min; + gf_low_pressure_this_dive = surface_pressure + buehlmann_config.gf_low_position_min; } void cache_deco_state(double tissue_tolerance, char **cached_datap) @@ -287,59 +247,20 @@ unsigned int deco_allowed_depth(double tissues_tolerance, double surface_pressur unsigned int depth; double pressure_delta; - pressure_delta = tissues_tolerance > surface_pressure ? tissues_tolerance - surface_pressure : 0.0; /* Avoid negative depths */ - - - /* gboolean below_gradient_limit; */ - /* double new_gradient_factor; */ - /* double pressure_delta = tissues_tolerance - surface_pressure; */ - /* struct dive_data mydata; */ - /* int bail = 1000; */ - - /* if (pressure_delta > 0) { */ - /* if (!smooth) { */ - /* multiples_of_3m = (pressure_delta + DIST_FROM_3_MTR) / 0.3; */ - /* depth = 3000 * multiples_of_3m; */ - /* } else { */ - /* depth = rel_mbar_to_depth(pressure_delta * 1000, dive); */ - /* } */ - /* } else { */ - /* depth = 0; */ - /* } */ - /* mydata.pressure = depth_to_mbar(depth, dive) / 1000.0; */ - /* mydata.surface = surface_pressure; */ - - /* new_gradient_factor = gradient_factor_calculation(&mydata); */ - /* below_gradient_limit = (new_gradient_factor < actual_gradient_limit(&mydata)); */ - /* while(!below_gradient_limit) */ - /* { */ - /* /\* we run into bugs where this turns into an infinite loop; so add */ - /* * some bailout code that prints a warning but prevents the code from hanging *\/ */ - /* if (--bail == 0) { */ - /* printf("WARNING!!!\n==========\nThe deco_allowed_depth() loop appears to hang.\nBailing out.\n"); */ - /* break; */ - /* } */ - /* if (!smooth) */ - /* mydata.pressure += PRESSURE_CHANGE_3M; */ - /* else */ - /* mydata.pressure += PRESSURE_CHANGE_3M / 30; /\* 4in / 10cm instead *\/ */ - /* new_gradient_factor = gradient_factor_calculation(&mydata); */ - /* below_gradient_limit = (new_gradient_factor < actual_gradient_limit(&mydata)); */ - /* } */ - /* depth = rel_mbar_to_depth((mydata.pressure - surface_pressure) * 1000, dive); */ + /* 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; + 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; + depth = buehlmann_config.last_deco_stop_in_mtr * 1000; return depth; } - void set_gf(double gflow, double gfhigh) { if (gflow != -1.0) |