[PULL REQUEST] VPM-B

[Jan Darowski]

> I think I've worked out at least one difference in the programs' algorithms,
> and sorry I doubt you'll like it.  Subsurface calculates required stops
> considering the ascent rate and the time to reach the stop.  The Fortran
> program calculates the 'instantaneous' ceiling, i.e. the depth corresponding
> to the tolerated ambient pressure according to the current allowable
> pressure gradient.  More fun!
>
> Which approach is more justified?  Debatable.  The method used by Subsurface
> should be 'better', but when the depth of the first stop/ceiling is given a
> special significance thanks to the Boyles law compensation process, I'm not
> so sure.  The 'instantaneous' ceiling method is more conservative, and,
> without having modified the code and tested, I'm guessing would produce deco
> schedules more consistent with other VPM-B programs.
>
> R
>

I expected something like this... calculations are checked, gradients
are checked. It had to be something "mechanical". For the examples
you've posted I got 16 vs 16min and 46 vs 49min after the fix (in
trial_ascent I changed the segment time to 0 and added one more place
for boyles_compensation).

Thanks a lot for this, I spent many days on searching for bugs in this
code. I suppose there can be some other small issues but this one
explains a lot.

Today there will be a patch for this.

-- 
Jan Darowski