diff options
Diffstat (limited to 'deco.c')
| -rw-r--r-- | deco.c | 85 |
1 files changed, 54 insertions, 31 deletions
@@ -129,6 +129,49 @@ static double tissue_tolerance_calc(const struct dive *dive) 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; +} + /* add period_in_seconds at the given pressure and gas to the deco calculation */ double add_segment(double pressure, const struct gasmix *gasmix, int period_in_seconds, int ccpo2, const struct dive *dive) { @@ -152,37 +195,17 @@ double add_segment(double pressure, const struct gasmix *gasmix, int period_in_s pphe *= f_dilutent; } } - if (period_in_seconds == 1) { /* one second interval during dive */ - for (ci = 0; ci < 16; ci++) { - if (ppn2 - tissue_n2_sat[ci] > 0) - tissue_n2_sat[ci] += buehlmann_config.satmult * (ppn2 - tissue_n2_sat[ci]) * - buehlmann_N2_factor_expositon_one_second[ci]; - else - tissue_n2_sat[ci] += buehlmann_config.desatmult * (ppn2 - tissue_n2_sat[ci]) * - buehlmann_N2_factor_expositon_one_second[ci]; - if (pphe - tissue_he_sat[ci] > 0) - tissue_he_sat[ci] += buehlmann_config.satmult * (pphe - tissue_he_sat[ci]) * - buehlmann_He_factor_expositon_one_second[ci]; - else - tissue_he_sat[ci] += buehlmann_config.desatmult * (pphe - tissue_he_sat[ci]) * - buehlmann_He_factor_expositon_one_second[ci]; - } - } else { /* all other durations */ - for (ci = 0; ci < 16; ci++) - { - if (ppn2 - tissue_n2_sat[ci] > 0) - tissue_n2_sat[ci] += buehlmann_config.satmult * (ppn2 - tissue_n2_sat[ci]) * - (1 - pow(2.0,(- period_in_seconds / (buehlmann_N2_t_halflife[ci] * 60)))); - else - tissue_n2_sat[ci] += buehlmann_config.desatmult * (ppn2 - tissue_n2_sat[ci]) * - (1 - pow(2.0,(- period_in_seconds / (buehlmann_N2_t_halflife[ci] * 60)))); - if (pphe - tissue_he_sat[ci] > 0) - tissue_he_sat[ci] += buehlmann_config.satmult * (pphe - tissue_he_sat[ci]) * - (1 - pow(2.0,(- period_in_seconds / (buehlmann_He_t_halflife[ci] * 60)))); - else - tissue_he_sat[ci] += buehlmann_config.desatmult * (pphe - tissue_he_sat[ci]) * - (1 - pow(2.0,(- period_in_seconds / (buehlmann_He_t_halflife[ci] * 60)))); - } + + for (ci = 0; ci < 16; ci++) { + double ppn2_oversat = ppn2 - tissue_n2_sat[ci]; + double pphe_oversat = pphe - 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 = ppn2_oversat > 0 ? buehlmann_config.satmult : buehlmann_config.desatmult; + double he_satmult = pphe_oversat > 0 ? buehlmann_config.satmult : buehlmann_config.desatmult; + + tissue_n2_sat[ci] += n2_satmult * ppn2_oversat * n2_f; + tissue_he_sat[ci] += he_satmult * pphe_oversat * he_f; } return tissue_tolerance_calc(dive); } |