diff options
Diffstat (limited to 'dive.c')
| -rw-r--r-- | dive.c | 101 |
1 files changed, 11 insertions, 90 deletions
@@ -1526,106 +1526,27 @@ int gasmix_distance(const struct gasmix *a, const struct gasmix *b) } /* fill_pressures(): Compute partial gas pressures in bar from gasmix and ambient pressures, possibly for OC or CCR, to be - * extended to PSCT. This function does the calculations of gass pressures applicable to a single point on the dive profile. - * The structure "pressures" is used to obtain data and to return calculated gas pressures to the calling software. + * extended to PSCT. This function does the calculations of gass pressures applicable to a single point on the dive profile. + * The structure "pressures" is used to return calculated gas pressures to the calling software. * Call parameters: po2 = po2 value applicable to the record in calling function * amb_pressure = ambient pressure applicable to the record in calling function * *pressures = structure for communicating o2 sensor values from and gas pressures to the calling function. * *mix = structure containing cylinder gas mixture information. - *dc = pointer to divecomputer structure. * This function called by: calculate_gas_information_new() in profile.c; add_segment() in deco.c. */ -extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2, const struct divecomputer *dc) -{ - double sensor_j, sump, midp, minp, maxp; - double diff_limit = 100; // The limit beyond which O2 sensor differences are considered significant (default = 100 mbar) - int num_of_diffs; // The number of unacceptable differences among the ogygen sensor partial pressure measurements - int i, j, np; - bool maxdif = false, mindif = false; - - if (dc->dctype == CCR) { // for CCR rebreathers.. - // Estimate the most reliable PO2, given the different oxygen partial pressure values from the O2 sensors - switch (dc->no_o2sensors) { - case 2: { // For 2 sensors: take the mean value of the two partial pressure sensors. - np = 0; - sump = 0; // This calculation allows that for some samples (especially at start of dive) with - for (j = 0; j < 2; j++) { // an inactive sensor, the sensor(s) with zero values are not used. - sensor_j = pressures->sensor[j]; - if (sensor_j) { - np++; - sump = sump + sensor_j; - } - } - if (np > 0) // if there is at least one sensor value - pressures->o2 = sump / np; // then calculate the mean, else -// else pressures->o2 = po2; // if there are no valid sensor values, the use the po2 parameter. - break; - } - case 3: { /* For 3 sensors: diff_limit is the critical limit indicating unacceptable difference (default = 100 mbar). - * a) If all three readings are within a range of diff_limit, then take the mean value. This - * includes the case where reading 1 is within diff_limit of reading 2; and reading 2 is - * within diff_limit of reading 3, but readings 1 and 3 differ by more than diff_limit. - * b) If one sensor differs by more than diff-limit from the other two, then take the mean - * of the closer two sensors and disregard the 3rd sensor, considered as an outlier. - * c) If all 3 sensors differ by more than diff_limit then take the mean of the 3 readings. */ - for (minp = 9999999999, maxp = -1, sump = 0, j = 0; j < 3; j++) { - sensor_j = pressures->sensor[j]; - if (sensor_j < minp) - minp = sensor_j; - if (sensor_j > maxp) - maxp = sensor_j; - sump = sump + sensor_j; // Find min, max and mid of p-values - } - midp = sump - minp - maxp; - num_of_diffs = 0; - if ((maxp - midp) > diff_limit) { - num_of_diffs++; - maxdif = true; - } - if ((midp - minp) > diff_limit) { - num_of_diffs++; - mindif = true; // Find no of unacceptable differences - } - switch (num_of_diffs) { - case 0: - ; - case 2: { - pressures->o2 = sump / 3; // 0 or 2 unacceptable differences: find mean of three values. - break; - } - case 1: { - if (maxdif) // 1 unacceptable difference: find mean of two closer values - pressures->o2 = (minp + midp) / 2; - if (mindif) - pressures->o2 = (maxp + midp) / 2; - break; - } - } //switch no_of_diffs - } - default: { // if # of sensors is 1 or unknown, simply take the value of the first sensor - if (pressures->sensor[0]) - pressures->o2 = pressures->sensor[0]; - else - pressures->o2 = po2; // if no sensor value found, then go to next section, esimating PO2 using depth. - } - } // switch dc->n0_o2_sensors - - pressures->he = (amb_pressure - pressures->o2) * (double)get_he(mix) / (1000 - get_o2(mix)); - pressures->n2 = amb_pressure - pressures->o2 - pressures->he; - - - } // if dc->type == CCR; Now pressures->o2 should be defined, based on direct measurements. - - if (po2) { // If we had a CCR dive (above) then pressures->o2 is defined, therefore this option is a fallback, - if (po2 >= amb_pressure || get_o2(mix) == 1000) // dependent on the po2 parameter in the call to this - pressures->o2 = amb_pressure; // function and applicable to non-CCR dives. +extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2) +{ + if (po2) { // This is probably a CCR dive where pressures->o2 is defined + if (po2 >= amb_pressure || get_o2(mix) == 1000) + pressures->o2 = amb_pressure; else pressures->o2 = po2; pressures->he = (amb_pressure - pressures->o2) * (double)get_he(mix) / (1000 - get_o2(mix)); pressures->n2 = amb_pressure - pressures->o2 - pressures->he; - } else if (!pressures->o2) { // Open circuit dives: no gas pressure values available, they need to be calculated - pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure; - pressures->he = get_he(mix) / 1000.0 * amb_pressure; + } else { + // Open circuit dives: no gas pressure values available, they need to be calculated + pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure; // These calculations are also used if the CCR calculation above.. + pressures->he = get_he(mix) / 1000.0 * amb_pressure; // ..returned a po2 of zero (i.e. o2 sensor data not resolvable) pressures->n2 = (1000 - get_o2(mix) - get_he(mix)) / 1000.0 * amb_pressure; } } |