Subsurface deco calculations

[Dirk Hohndel]

On Wed, Feb 08, 2017 at 11:24:07PM +0800, Miika Turkia wrote:
> Now I had a change to download the OSTC to an empty log file. Looks
> like the index and gas mixes are correct in this case:
> ---8<---
> <dive number='1' date='2017-02-01' time='15:00:00' duration='71:58 min'>
>   <cylinder size='11.094 l' workpressure='206.843 bar' description='AL80' />
>   <cylinder size='11.094 l' workpressure='206.843 bar'
> description='AL80' o2='32.0%' />
>   <cylinder size='11.094 l' workpressure='206.843 bar'
> description='AL80' o2='31.0%' />
>   <cylinder size='11.094 l' workpressure='206.843 bar' description='AL80' />
>   <cylinder size='11.094 l' workpressure='206.843 bar' description='AL80' />
>   <divecomputer model='Heinrichs Weikamp OSTC Sport'
> deviceid='ae480b5b' diveid='ce655d8f'>
> ...
>     <event time='0:02 min' type='25' flags='2' name='gaschange'
> cylinder='1' o2='32.0%' />
> ---8<---
> 
> So the index used is correctly 1 with o2 32%. Only used cylinder was
> that 32% as I find it easier to choose one of the common mixes than
> adjusting the mix for first cylinder. However, with Vyper the used
> cylinder index was 0 as that was the 32% mix in that computer. And
> that is the only cylinder stored in the log in my original DL.
> 
> Should we do the merge more intelligently mapping the cylinder indexes
> to match the gas mixes, or should I start using same cylinder indexes
> on different DCs?

I know that we used to do this correctly, because Linus and I were diving
together when I had four (or so) dive computers with me which had the
gases in different order... that's when he wrote the initial merging code.

So I'm thinking that this might have gotten broken recently :-/

Definitely something where we should create a test that merges two dives
with different tank numbering / order and make sure that the result is
correct.

/D