diff options
Diffstat (limited to 'core/dive.c')
| -rw-r--r-- | core/dive.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/core/dive.c b/core/dive.c index 84acecb38..54d2a00f4 100644 --- a/core/dive.c +++ b/core/dive.c @@ -1172,6 +1172,21 @@ static void sanitize_cylinder_info(struct dive *dive) } } +/* Perform isobaric counterdiffusion calculations for gas changes in trimix dives. + * Here we use the rule-of-fifths where, during a change involving trimix gas, the increase in nitrogen + * should not exceed one fifth of the decrease in helium. + * Parameters: 1) pointers to two gas mixes, the gas being switched from and the gas being switched to. + * 2) a pointer to an icd_data structure. + * Output: i) The icd_data stucture is filled with the delta_N2 and delta_He numbers (as permille). + * ii) Function returns a boolean indicating an exceeding of the rule-of-fifths. False = no icd problem. + */ +bool isobaric_counterdiffusion(struct gasmix *oldgasmix, struct gasmix *newgasmix, struct icd_data *results) +{ + results->dN2 = get_he(oldgasmix) + get_o2(oldgasmix) - get_he(newgasmix) - get_o2(newgasmix); + results->dHe = get_he(newgasmix) - get_he(oldgasmix); + return get_he(oldgasmix) && results->dN2 > 0 && 5 * results->dN2 > -results->dHe; +} + /* some events should never be thrown away */ static bool is_potentially_redundant(struct event *event) { |