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CNS calculation fix

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Identify previous dives for CNS calculation in a similar way as it
is done for previous dives for deco calculation.
This is done to identify the previous dives dynamically when moving
around date/time of a dive in the planner.

Signed-off-by: Stefan Fuchs <sfuchs@gmx.de>
This commit is contained in:
Stefan Fuchs 2017-10-02 20:35:21 +02:00 committed by Robert C. Helling
parent 4158a4c7de
commit 7a82103c99
1 changed files with 137 additions and 31 deletions
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168
core/divelist.c
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@ -205,42 +205,19 @@ int const cns_table[][3] = {
{ 600, 720 * 60, 720 * 60 }
};
/* this only gets called if dive->maxcns == 0 which means we know that
* none of the divecomputers has tracked any CNS for us
* so we calculated it "by hand" */
static int calculate_cns(struct dive *dive)
/* Calculate the CNS for a single dive */
double calculate_cns_dive(struct dive *dive)
{
int i, divenr;
int n;
size_t j;
double cns = 0.0;
struct divecomputer *dc = &dive->dc;
struct dive *prev_dive;
timestamp_t endtime;
/* shortcut */
if (dive->cns)
return dive->cns;
/*
* Do we start with a cns loading from a previous dive?
* Check if we did a dive 12 hours prior, and what cns we had from that.
* Then apply ha 90min halftime to see whats left.
*/
divenr = get_divenr(dive);
if (divenr) {
prev_dive = get_dive(divenr - 1);
if (prev_dive) {
endtime = dive_endtime(prev_dive);
if (dive->when < (endtime + 3600 * 12)) {
cns = calculate_cns(prev_dive);
cns = cns * 1 / pow(2, (dive->when - endtime) / (90.0 * 60.0));
}
}
}
/* Caclulate the cns for each sample in this dive and sum them */
for (i = 1; i < dc->samples; i++) {
double cns = 0.0;
/* Caclulate the CNS for each sample in this dive and sum them */
for (n = 1; n < dc->samples; n++) {
int t;
int po2;
struct sample *sample = dc->sample + i;
struct sample *sample = dc->sample + n;
struct sample *psample = sample - 1;
t = sample->time.seconds - psample->time.seconds;
if (sample->setpoint.mbar) {
@ -259,6 +236,135 @@ static int calculate_cns(struct dive *dive)
j--;
cns += ((double)t) / ((double)cns_table[j][1]) * 100;
}
return cns;
}
/* this only gets called if dive->maxcns == 0 which means we know that
* none of the divecomputers has tracked any CNS for us
* so we calculated it "by hand" */
static int calculate_cns(struct dive *dive)
{
int i, divenr;
double cns = 0.0;
timestamp_t last_starttime, last_endtime = 0;
/* shortcut */
if (dive->cns)
return dive->cns;
divenr = get_divenr(dive);
i = divenr >= 0 ? divenr : dive_table.nr;
#if DECO_CALC_DEBUG & 2
if (i >= 0 && i < dive_table.nr)
printf("\n\n*** CNS for dive #%d %d\n", i, get_dive(i)->number);
else
printf("\n\n*** CNS for dive #%d\n", i);
#endif
/* Look at next dive in dive list table and correct i when needed */
while (i < dive_table.nr - 1) {
struct dive *pdive = get_dive(i);
if (!pdive || pdive->when > dive->when)
break;
i++;
}
/* Look at previous dive in dive list table and correct i when needed */
while (i > 0) {
struct dive *pdive = get_dive(i - 1);
if (!pdive || pdive->when < dive->when)
break;
i--;
}
#if DECO_CALC_DEBUG & 2
printf("Dive number corrected to #%d\n", i);
#endif
last_starttime = dive->when;
/* Walk backwards to check previous dives - how far do we need to go back? */
while (i--) {
if (i == divenr && i > 0)
i--;
#if DECO_CALC_DEBUG & 2
printf("Check if dive #%d %d has to be considered as prev dive: ", i, get_dive(i)->number);
#endif
struct dive *pdive = get_dive(i);
/* we don't want to mix dives from different trips as we keep looking
* for how far back we need to go */
if (dive->divetrip && pdive->divetrip != dive->divetrip) {
#if DECO_CALC_DEBUG & 2
printf("No - other dive trip\n");
#endif
continue;
}
if (!pdive || pdive->when >= dive->when || dive_endtime(pdive) + 12 * 60 * 60 < last_starttime) {
#if DECO_CALC_DEBUG & 2
printf("No\n");
#endif
break;
}
last_starttime = pdive->when;
#if DECO_CALC_DEBUG & 2
printf("Yes\n");
#endif
}
/* Walk forward and add dives and surface intervals to CNS */
while (++i < dive_table.nr) {
#if DECO_CALC_DEBUG & 2
printf("Check if dive #%d %d will be really added to CNS calc: ", i, get_dive(i)->number);
#endif
struct dive *pdive = get_dive(i);
/* again skip dives from different trips */
if (dive->divetrip && dive->divetrip != pdive->divetrip) {
#if DECO_CALC_DEBUG & 2
printf("No - other dive trip\n");
#endif
continue;
}
/* Don't add future dives */
if (pdive->when >= dive->when) {
#if DECO_CALC_DEBUG & 2
printf("No - future or same dive\n");
#endif
break;
}
/* Don't add the copy of the dive itself */
if (i == divenr) {
#if DECO_CALC_DEBUG & 2
printf("No - copy of dive\n");
#endif
continue;
}
#if DECO_CALC_DEBUG & 2
printf("Yes\n");
#endif
/* CNS reduced with 90min halftime during surface interval */
if (last_endtime)
cns /= pow(2, (pdive->when - last_endtime) / (90.0 * 60.0));
#if DECO_CALC_DEBUG & 2
printf("CNS after surface interval: %f\n", cns);
#endif
cns += calculate_cns_dive(pdive);
#if DECO_CALC_DEBUG & 2
printf("CNS after previous dive: %f\n", cns);
#endif
last_starttime = pdive->when;
last_endtime = dive_endtime(pdive);
}
/* CNS reduced with 90min halftime during surface interval */
if (last_endtime)
cns /= pow(2, (dive->when - last_endtime) / (90.0 * 60.0));
#if DECO_CALC_DEBUG & 2
printf("CNS after last surface interval: %f\n", cns);
#endif
cns += calculate_cns_dive(dive);
#if DECO_CALC_DEBUG & 2
printf("CNS after dive: %f\n", cns);
#endif
/* save calculated cns in dive struct */
dive->cns = lrint(cns);
return dive->cns;