static double tissue_tolerance_calc(const struct dive *dive) { int ci = -1; double tissue_inertgas_saturation, buehlmann_inertgas_a, buehlmann_inertgas_b; 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; for (ci = 0; ci < 16; ci++) { double tolerated; tissue_inertgas_saturation = tissue_n2_sat[ci] + tissue_he_sat[ci]; buehlmann_inertgas_a = ((buehlmann_N2_a[ci] * tissue_n2_sat[ci]) + (buehlmann_He_a[ci] * tissue_he_sat[ci])) / tissue_inertgas_saturation; buehlmann_inertgas_b = ((buehlmann_N2_b[ci] * tissue_n2_sat[ci]) + (buehlmann_He_b[ci] * tissue_he_sat[ci])) / tissue_inertgas_saturation; /* tolerated = (tissue_inertgas_saturation - buehlmann_inertgas_a) * buehlmann_inertgas_b; */ #if !GF_LOW_AT_MAXDEPTH lowest_ceiling = (buehlmann_inertgas_b * tissue_inertgas_saturation - gf_low * buehlmann_inertgas_a * buehlmann_inertgas_b) / ((1.0 - buehlmann_inertgas_b) * gf_low + buehlmann_inertgas_b); if (lowest_ceiling > gf_low_pressure_this_dive) gf_low_pressure_this_dive = lowest_ceiling; #endif tolerated = (-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)); tolerated_by_tissue[ci] = tolerated; if (tolerated > ret_tolerance_limit_ambient_pressure) { ci_pointing_to_guiding_tissue = ci; ret_tolerance_limit_ambient_pressure = tolerated; } } return ret_tolerance_limit_ambient_pressure; }
/* Let's try to do some deco calculations. */ void calculate_deco_information(struct dive *dive, struct divecomputer *dc, struct plot_info *pi, bool print_mode) { int i, count_iteration = 0; double surface_pressure = (dc->surface_pressure.mbar ? dc->surface_pressure.mbar : get_surface_pressure_in_mbar(dive, true)) / 1000.0; int last_ndl_tts_calc_time = 0; int first_ceiling = 0; bool first_iteration = true; int final_tts = 0 , time_clear_ceiling = 0, time_deep_ceiling = 0, deco_time = 0, prev_deco_time = 10000000; char *cache_data_initial = NULL; /* For VPM-B outside the planner, cache the initial deco state for CVA iterations */ if (prefs.deco_mode == VPMB && !in_planner()) cache_deco_state(&cache_data_initial); /* For VPM-B outside the planner, iterate until deco time converges (usually one or two iterations after the initial) * Set maximum number of iterations to 10 just in case */ while ((abs(prev_deco_time - deco_time) >= 30) && (count_iteration < 10)) { for (i = 1; i < pi->nr; i++) { struct plot_data *entry = pi->entry + i; int j, t0 = (entry - 1)->sec, t1 = entry->sec; int time_stepsize = 20; entry->ambpressure = depth_to_bar(entry->depth, dive); entry->gfline = MAX((double)prefs.gflow, (entry->ambpressure - surface_pressure) / (gf_low_pressure_this_dive - surface_pressure) * (prefs.gflow - prefs.gfhigh) + prefs.gfhigh) * (100.0 - AMB_PERCENTAGE) / 100.0 + AMB_PERCENTAGE; if (t0 > t1) { fprintf(stderr, "non-monotonous dive stamps %d %d\n", t0, t1); int xchg = t1; t1 = t0; t0 = xchg; } if (t0 != t1 && t1 - t0 < time_stepsize) time_stepsize = t1 - t0; for (j = t0 + time_stepsize; j <= t1; j += time_stepsize) { int depth = interpolate(entry[-1].depth, entry[0].depth, j - t0, t1 - t0); add_segment(depth_to_bar(depth, dive), &dive->cylinder[entry->cylinderindex].gasmix, time_stepsize, entry->o2pressure.mbar, dive, entry->sac); if ((t1 - j < time_stepsize) && (j < t1)) time_stepsize = t1 - j; } if (t0 == t1) { entry->ceiling = (entry - 1)->ceiling; } else { /* Keep updating the VPM-B gradients until the start of the ascent phase of the dive. */ if (prefs.deco_mode == VPMB && !in_planner() && (entry - 1)->ceiling >= first_ceiling && first_iteration == true) { nuclear_regeneration(t1); vpmb_start_gradient(); /* For CVA calculations, start by guessing deco time = dive time remaining */ deco_time = pi->maxtime - t1; vpmb_next_gradient(deco_time, surface_pressure / 1000.0); } entry->ceiling = deco_allowed_depth(tissue_tolerance_calc(dive, depth_to_bar(entry->depth, dive)), surface_pressure, dive, !prefs.calcceiling3m); /* If using VPM-B outside the planner, take first_ceiling_pressure as the deepest ceiling */ if (prefs.deco_mode == VPMB && !in_planner()) { if (entry->ceiling >= first_ceiling) { time_deep_ceiling = t1; first_ceiling = entry->ceiling; first_ceiling_pressure.mbar = depth_to_mbar(first_ceiling, dive); if (first_iteration) { nuclear_regeneration(t1); vpmb_start_gradient(); /* For CVA calculations, start by guessing deco time = dive time remaining */ deco_time = pi->maxtime - t1; vpmb_next_gradient(deco_time, surface_pressure / 1000.0); } } // Use the point where the ceiling clears as the end of deco phase for CVA calculations if (entry->ceiling > 0) time_clear_ceiling = 0; else if (time_clear_ceiling == 0) time_clear_ceiling = t1; } } for (j = 0; j < 16; j++) { double m_value = buehlmann_inertgas_a[j] + entry->ambpressure / buehlmann_inertgas_b[j]; entry->ceilings[j] = deco_allowed_depth(tolerated_by_tissue[j], surface_pressure, dive, 1); entry->percentages[j] = tissue_inertgas_saturation[j] < entry->ambpressure ? tissue_inertgas_saturation[j] / entry->ambpressure * AMB_PERCENTAGE : AMB_PERCENTAGE + (tissue_inertgas_saturation[j] - entry->ambpressure) / (m_value - entry->ambpressure) * (100.0 - AMB_PERCENTAGE); } /* should we do more calculations? * We don't for print-mode because this info doesn't show up there * If the ceiling hasn't cleared by the last data point, we need tts for VPM-B CVA calculation * It is not necessary to do these calculation on the first VPMB iteration, except for the last data point */ if ((prefs.calcndltts && !print_mode && (prefs.deco_mode != VPMB || in_planner() || !first_iteration)) || (prefs.deco_mode == VPMB && !in_planner() && i == pi->nr - 1)) { /* only calculate ndl/tts on every 30 seconds */ if ((entry->sec - last_ndl_tts_calc_time) < 30 && i != pi->nr - 1) { struct plot_data *prev_entry = (entry - 1); entry->stoptime_calc = prev_entry->stoptime_calc; entry->stopdepth_calc = prev_entry->stopdepth_calc; entry->tts_calc = prev_entry->tts_calc; entry->ndl_calc = prev_entry->ndl_calc; continue; } last_ndl_tts_calc_time = entry->sec; /* We are going to mess up deco state, so store it for later restore */ char *cache_data = NULL; cache_deco_state(&cache_data); calculate_ndl_tts(entry, dive, surface_pressure); if (prefs.deco_mode == VPMB && !in_planner() && i == pi->nr - 1) final_tts = entry->tts_calc; /* Restore "real" deco state for next real time step */ restore_deco_state(cache_data); free(cache_data); } } if (prefs.deco_mode == VPMB && !in_planner()) { prev_deco_time = deco_time; // Do we need to update deco_time? if (final_tts > 0) deco_time = pi->maxtime + final_tts - time_deep_ceiling; else if (time_clear_ceiling > 0) deco_time = time_clear_ceiling - time_deep_ceiling; vpmb_next_gradient(deco_time, surface_pressure / 1000.0); final_tts = 0; last_ndl_tts_calc_time = 0; first_ceiling = 0; first_iteration = false; count_iteration ++; restore_deco_state(cache_data_initial); } else { // With Buhlmann, or not in planner, iterating isn't needed. This makes the while condition false. prev_deco_time = deco_time = 0; } } free(cache_data_initial); #if DECO_CALC_DEBUG & 1 dump_tissues(); #endif }