Patch: consider water vapor in deco

[Robert C. Helling]

Hi,



when we introduced the general helper function for partial pressures, we did no longer subtract the water vapor pressure from the ambient pressure as we had done before. This patch corrects this.

I came across this because of the complaint that our planner is not as snappy anymore as it was. As I said before, I am not sure I can confirm this, as also before, there was some lag in planning dives with 10+h deco (we might still improve on that by first unceasing the step size for longer dives and only go back to one minute steps when the mouse no longer moves, but ok we might…). So I did some testing with dives in the 90m/70min range and found that deco times were significantly longer than what I saw in some random other dive planner (750min vs almost 900min). After some bisecting I found that the omission of the water vapor is responsible for that (with it included I produce exactly the same plan as with BalticDeco on my IPhone). I had always thought that even though Buehlmann has the water vapor correction in his book its effect was actually negligible but I had to learn it is not.

So this has some effect on deco times (in the 10% range in this example) and should thus have a similar effect on computation time but I doubt this solves the “planner is slow” problem. In order for me to be able to track this down, could somebody please point out a commit to me in which the planner was significantly snappier?

Thanks
Robert




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Robert C. Helling     Elite Master Course Theoretical and Mathematical Physics
                      Scientific Coordinator
                      Ludwig Maximilians Universitaet Muenchen, Dept. Physik
                      Phone: +49 89 2180-4523  Theresienstr. 39, rm. B339
                      http://www.atdotde.de

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