Jan Schubert Jan.Schubert at GMX.li
Sun Jan 13 11:34:32 PST 2013

On 01/13/13 20:28, Dirk Hohndel wrote:
> On Jan 13, 2013, at 10:57 AM, Jan Schubert wrote:
>> This is a approach to get more familar with the code by implementing
>> some basic stuff showing MOD, EAD, AND and EADD:
>> - MOD: Maximum Operation Depth based on a limit of 1.6bar as of now
>> (will think about to make this configurable soon)
>> - EAD: Equivalent Air Depth considering N2 and (!) O2 narcotic
>> - END: Equivalent Nitrogen (Narcotic) Depth considering just N2 narcotic
>> (ignoring O2)
>> - EADD: Equivalent Air Density Depth
>> Please note that some people and even diving organisations have opposite
>> definitions for EAD and END, but considering A stands for Air, I choosed
>> the above. And considerung N for Nitrogen it also fits in this scheme.
> Ok. You went with one config option to display all of them. Maybe not a bad idea.
> But hardcoding the 1.6 is - most non-tech divers (and even some tech divers like
> myself) want 1.4 for that…

Sure, thatsway it should be made configurable, will do this soon.

>> Some notes:
>> This patch moves N2_IN_AIR from deco.c to dive.h as this is already and
>> might be used in several places. It also respecifies N2_IN_AIR to a more
>> correct value of 78,084%, the former one also included all other gases
>> than oxygen appearing in air. If someone needs to use the former value
>> it would be more correct to use 1-O2_IN_AIR instead.
> I'm surprised that you think that a difference of three and a half tenth of a permille 
> matters… even at 100m that will change the calculated value by less than one
> percent...

It's just more correct. We could use 0,8 also, why not use a correct
value if we have one? Might be used in several other ways as well.

>> It took me some time to recognize that depth is always stored in mm
>> independent of using metric or imperial units and the conversion is not
>> done automatically when printing/displaying the graph.
>> All results rounded down to full meters. As the conversion to feet is
>> done afterwards the depth in feet might me 1 or 2 feet to shallow sometimes.
> Don't do that, please. Round when you display, not when you calculate. 

OK, will adapt this.

> I also noticed that the 20cm offset for ceilings is hidden in this patch.
> I don't want that hardcoded in the algorithm.

Sorry, please ignore this, has not been in by purpose.


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