Problems with ceiling for CCR dive

[Robert Helling]

On 13.10.2014, at 08:49, Willem Ferguson <willemferguson at zoology.up.ac.za> wrote:

Willem,

> I think we have different understandings of the logic.


I have just tried to fix the partial pressure calculation but stopped since I found it is missing more than I thought.

As it turns out your patch breaks the ceiling calculation not only for CCR dives but for all dives (at least also for my OC dives).

Let me point out a few things:

1) Your sensor data never reaches fill_pressures: You make the pressures struct (and I would like to add that using one structure to both pass data in and out of the function does not sound like such a great idea to me) be a member of the entry struct. But then, that gets never used as add_segments gets called which does not now about entry and thus creates a new pressures struct which has uninitialized values in it.

One simple way to fix this would be to do the sensor voting logic not in fill_pressures but in a separate function and then feed the resulting majority vote for the po2 into add_segment. For example you could call that from profile.c with the entry as argument (or just a pointer to the sensors array) to obtain the po2. Then you could leave the data of the individual sensors out to the pressures struct.

2) I can unbreak the OC part by at least

th-ws-tmpim01:subsurface helling$ git diff
diff --git a/dive.c b/dive.c
index 4d906e5..d624cce 100644
--- a/dive.c
+++ b/dive.c
@@ -1623,7 +1623,7 @@ extern void fill_pressures(struct gas_pressures *pressures, const double amb_pre
                        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
+       } else { // 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;
                pressures->n2 = (1000 - get_o2(mix) - get_he(mix)) / 1000.0 * amb_pressure;

3) In the case of two sensors, why does your for loop iterate over three sensors?

Best
Robert

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Robert C. Helling     Elite Master Course Theoretical and Mathematical Physics
                      Scientific Coordinator
                      Ludwig Maximilians Universitaet Muenchen, Dept. Physik
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