[PATCH]Re: Deco calculation for repetitive dive - strange effect

Dirk Hohndel dirk at hohndel.org
Thu Feb 9 21:26:30 PST 2017


On Tue, Feb 07, 2017 at 09:24:34PM +0100, Robert Helling wrote:
> Hi,
> 
> > On 07 Feb 2017, at 19:53, Stefan Fuchs <sfuchs at gmx.de> wrote:
> > 
> > I understand that we don't want to tweak the VPM-B implementation to make the results look nicer w/o knowing if this is then still in line with the ideas of "the real model" and I fully agree to this. But maybe based on Linus finding there is until now really a misunderstanding regarding the implementation for this specific detail?
> 
> I guess (as so often) Linus is right, we should reset the state between dives (except of course tissue saturations) to get rid of this anomaly, and if other code does that even better.
> 
> I attach a patch that does this.
> 
> There is probably no point in arguing about the original model since that IIIRC does not consider repetitive dives but I have to check the docs again. In any case, I would say this still shows how strange the model is: We have to artificially reset parameters between two dives. But of course „between dives“ can be somewhat arbitrary: If you only surface for a few minutes and then descend again, are these „two dives“ (which require a reset in between and how does your body know that it has to reset itself, after all this is what we are supposed to simulate) or is this a single dive (without reset)? What I take away is the impression that this does not make a lot of sense.
> 
> But yes, please take this patch for master.

So, err, should I, or shouldn't I? The discussion left me thinking that
VPM-B clearly is even more bogus and weird than I thought before, but I'm
not sure we came to a conclusion what to do here...

Thanks

/D


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