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Calculate OTUs for every dive

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The calculation assumes that the cylinderindex in each sample tells us
which PO2 the dive was breathing at that time. This needs to be verified
with dives where there is an actual gas switch.

No idea where to display them, yet. Far fewer people will care about this
than care about SAC - does this still rate a spot in the dive_list?
I guess I could make it part of the dive_info - but it's not editable.
It doesn't seem to fit with the equipment page (even though this is the
one editable field that is related - nitrox %)

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
This commit is contained in:
Dirk Hohndel 2011-09-22 13:45:53 -07:00
parent 15463fdeb2
commit a93641b722
3 changed files with 29 additions and 2 deletions
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6
dive.h
View file

@ -134,6 +134,11 @@ static inline int to_PSI(pressure_t pressure)
return pressure.mbar * 0.0145037738 + 0.5; return pressure.mbar * 0.0145037738 + 0.5;
} }
static inline double to_ATM(pressure_t pressure)
{
return pressure.mbar / 1013.25;
}
struct sample { struct sample {
duration_t time; duration_t time;
depth_t depth; depth_t depth;
@ -156,6 +161,7 @@ struct dive {
depth_t visibility; depth_t visibility;
temperature_t airtemp, watertemp; temperature_t airtemp, watertemp;
cylinder_t cylinder[MAX_CYLINDERS]; cylinder_t cylinder[MAX_CYLINDERS];
double otu;
int samples, alloc_samples; int samples, alloc_samples;
struct sample sample[]; struct sample sample[];
}; };

21
divelist.c
View file

@ -14,6 +14,7 @@
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
#include <time.h> #include <time.h>
#include <math.h>
#include "divelist.h" #include "divelist.h"
#include "dive.h" #include "dive.h"
@ -222,6 +223,25 @@ static void sac_data_func(GtkTreeViewColumn *col,
g_object_set(renderer, "text", buffer, NULL); g_object_set(renderer, "text", buffer, NULL);
} }
/* calculate OTU for a dive */
static double calculate_otu(struct dive *dive)
{
int i;
double otu = 0.0;
for (i = 1; i < dive->samples; i++) {
int t;
double po2;
struct sample *sample = dive->sample + i;
struct sample *psample = sample - 1;
t = sample->time.seconds - psample->time.seconds;
po2 = dive->cylinder[sample->cylinderindex].gasmix.o2.permille / 1000.0 *
(sample->depth.mm + 10000) / 10000.0;
if (po2 >= 0.5)
otu += pow(po2 - 0.5, 0.83) * t / 30.0;
}
return otu;
}
/* /*
* Return air usage (in liters). * Return air usage (in liters).
*/ */
@ -389,6 +409,7 @@ static void fill_dive_list(void)
for (i = 0; i < dive_table.nr; i++) { for (i = 0; i < dive_table.nr; i++) {
struct dive *dive = dive_table.dives[i]; struct dive *dive = dive_table.dives[i];
dive->otu = calculate_otu(dive);
gtk_list_store_append(store, &iter); gtk_list_store_append(store, &iter);
gtk_list_store_set(store, &iter, gtk_list_store_set(store, &iter,
DIVE_INDEX, i, DIVE_INDEX, i,

4
parse-xml.c
View file

@ -1051,7 +1051,7 @@ static void match_standard_cylinder(cylinder_type_t *type)
return; return;
cuft = type->size.mliter / 28317.0; cuft = type->size.mliter / 28317.0;
cuft *= type->workingpressure.mbar / 1013.25; cuft *= to_ATM(type->workingpressure);
psi = type->workingpressure.mbar / 68.95; psi = type->workingpressure.mbar / 68.95;
switch (psi) { switch (psi) {
@ -1106,7 +1106,7 @@ static void sanitize_cylinder_type(cylinder_type_t *type)
if (input_units.volume == CUFT || import_source == SUUNTO) { if (input_units.volume == CUFT || import_source == SUUNTO) {
volume_of_air = type->size.mliter * 28.317; /* milli-cu ft to milliliter */ volume_of_air = type->size.mliter * 28.317; /* milli-cu ft to milliliter */
atm = type->workingpressure.mbar / 1013.25; /* working pressure in atm */ atm = to_ATM(type->workingpressure); /* working pressure in atm */
volume = volume_of_air / atm; /* milliliters at 1 atm: "true size" */ volume = volume_of_air / atm; /* milliliters at 1 atm: "true size" */
type->size.mliter = volume + 0.5; type->size.mliter = volume + 0.5;
} }