I have been doing some testing, as you have seen from emails on the mail
list and have looked at the existing Subsurface code in divelist.c.
With respect to the calculation of CNS%, your and my calculations are
identical EXCEPT that, for a specific PO2, you only use the next-lower
tabulated maximum time and do not interpolate to provide for a PO2 value
that is intermediate between two tabulated max-time values (line 214 in
divelist.c). We use the same table originating from the NOAA Diving
Manual and I think that is safe. Therefore the Subsurface CNS% values
are slightly conservative.
With respect to the calculation of OTUs, you use an analogous but
different formula from the one provided in the Baker document. At this
stage I would not say that the formula in the existing code (line 165 in
divelist.c) is better or worse than that of the Baker document (taking
into account other bugs in the Baker document). But do you have any idea
where the formula in divelist.c comes from? I would like to do more
reading around the issue to come to a sensible conclusion about these
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