Re: Scaling of cylinder pressures in profile
On Montag, 11. November 2019 12:50:25 CET Willem Ferguson wrote: > On 2019/11/11 11:38, Berthold Stoeger wrote: > > > What happens now is that this part of the code actually starts to work. > > But if you don't have an "air integrated" computer, you will not have > > pressure readings, > > But, for non-AI dives, you have start and end pressures for each > cylinder, typed in manually. For AI dives (as far as I can make out), > start and end pressures are evaluated by the software. Indeed, potential fix in this PR: https://github.com/Subsurface-divelog/subsurface/pull/2369 I think that was a bug from the beginning of this code - it's just that nobody ever noticed that min_pressure is always 0. Berthold ___ subsurface mailing list subsurface@subsurface-divelog.org http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
Re: Scaling of cylinder pressures in profile
On 2019/11/11 11:38, Berthold Stoeger wrote:
On Montag, 11. November 2019 09:05:18 CET Willem Ferguson wrote:
There appears to be a bug in Subsurface. Check the attached dive log and
the rendering of cylinder pressures. Also see attached screenshot. I did
not notice this until now. Is it perhaps the last merge base don my PR
that causes this?
Funnily enough, this seems to be an old bug that now becomes active. Consider
this code in calculate_max_limits_new():
for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
int mbar = dive->cylinder[cyl].start.mbar;
if (mbar > maxpressure)
maxpressure = mbar;
if (mbar < minpressure)
minpressure = mbar;
}
If you have less than MAX_CYLINDERS cylinders (i.e. in 100% of cases), mbar
will evaluate to 0. Thus, minpressure will be 0 in all cases. This code never
worked.
What happens now is that this part of the code actually starts to work. But if
you don't have an "air integrated" computer, you will not have pressure
readings,
But, for non-AI dives, you have start and end pressures for each
cylinder, typed in manually. For AI dives (as far as I can make out),
start and end pressures are evaluated by the software.
so minpressure will remain the minimum start-pressure of any of your
cylinders.
This appears to be the appropriate procedure.
That gives the funky effect you see.
Possibility 1: if minpressure == maxpressure (meaning that we found no
pressure reading), set minpressure to 0. This will restore the old behavior
for non-air integrated computers.
Possibility 2: correctly determine the minimum pressure by looking at the
profile data not the *events*.
I think the profile data are actually used to initialise the min and max
pressures for an instrumented cylinder and it might therefore not be
necessary to inspect the actual cylinder pressure values during the
dive. Which events do you refer to here? Gas change events? I know for
some dive computers an automatic gas change event is created right at
the start of the dive.
Is it necessary that the loop should go all the way to MAX_CYLINDERS ??
Surely, if there are only two cylinders then it could stop at an index
of 1 ?? The question, of course, is how would dives behave that have
some pressure for one or 2 cylinders but no pressure data for other.
That is the situation that I am in with a sidemount configuration. Since
I have only one sensor, I need to write the data for the second cylinder
on my slate and then enter that by hand in the Equipment panel.
Kind regards,
willem
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Re: Scaling of cylinder pressures in profile
On Montag, 11. November 2019 09:05:18 CET Willem Ferguson wrote:
> There appears to be a bug in Subsurface. Check the attached dive log and
> the rendering of cylinder pressures. Also see attached screenshot. I did
> not notice this until now. Is it perhaps the last merge base don my PR
> that causes this?
Funnily enough, this seems to be an old bug that now becomes active. Consider
this code in calculate_max_limits_new():
for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
int mbar = dive->cylinder[cyl].start.mbar;
if (mbar > maxpressure)
maxpressure = mbar;
if (mbar < minpressure)
minpressure = mbar;
}
If you have less than MAX_CYLINDERS cylinders (i.e. in 100% of cases), mbar
will evaluate to 0. Thus, minpressure will be 0 in all cases. This code never
worked.
What happens now is that this part of the code actually starts to work. But if
you don't have an "air integrated" computer, you will not have pressure
readings, so minpressure will remain the minimum start-pressure of any of your
cylinders.
That gives the funky effect you see.
Possibility 1: if minpressure == maxpressure (meaning that we found no
pressure reading), set minpressure to 0. This will restore the old behavior
for non-air integrated computers.
Possibility 2: correctly determine the minimum pressure by looking at the
profile data not the events.
Berthold
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Re: Scaling of cylinder pressures in profile
Dear Willem, On Montag, 11. November 2019 09:05:18 CET Willem Ferguson wrote: > There appears to be a bug in Subsurface. Check the attached dive log and > the rendering of cylinder pressures. Also see attached screenshot. I did > not notice this until now. Is it perhaps the last merge base don my PR > that causes this? That's most certainly the MAX_CYLINDERS changes. I will look into it in the evening. Berthold ___ subsurface mailing list subsurface@subsurface-divelog.org http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
