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Subsurface's Buhlmann ZH-L16 algorithm implementation

Discussion in 'Dive Software' started by stepfen, Apr 29, 2019.

  1. stepfen

    stepfen Barracuda

    # of Dives: 100 - 199
    Location: Greece
    361
    160
    43
    Hello everybody,
    As I do my Extended Range Nitrox course, I started experimenting with subsurface's planner. So far I've been keying in different values (depths, times, GFs, gasses etc) and observe the results. For interesting ones, I usually would just print the resulting plan to pdf files so that I can easily compare with each other.
    Until this morning I have never saved an actual plan. So far so good. Today I tried to save a dive and I get the following warning in the Notes section:

    "DISCLAIMER / WARNING: THIS IS A NEW IMPLEMENTATION OF THE BUHLMANN ALGORITHM AND A DIVE PLANNER IMPLEMENTATION BASED ON THAT WHICH HAS RECEIVED ONLY A LIMITED AMOUNT OF TESTING. WE STRONGLY RECOMMEND NOT TO PLAN DIVES SIMPLY BASED ON THE RESULTS GIVEN HERE." !!

    This warning comes only when I save a dive/plan. During the planing/printing of dives no such warnings are given - hence I haven't seen this before.

    So the question is, is this just a usual liability avoidance thing from Subsurface's creators, or indeed there have been important changes in the implementation of the algorithm recently that haven't been adequately tested yet? If that's the case, it seems that subsurface can only be used in conjunction with other software.
    Is this something temporal or ??

    I haven't done a real deco dive yet (only simulations so far), but sooner or later I will start planing dives with software and I was hopping to be able to use subsurface for this.

    Thanks for any info.
     
  2. atdotde

    atdotde Solo Diver

    # of Dives: 200 - 499
    Location: Munich, Germany
    131
    99
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    Read this as the usual disclaimer. We did our best but software programming is error prone. And a human body is much more complicated than what can be simulated in a computer program. So don't blame us if you get bent.
     
    taimen, D_Fresh and rhwestfall like this.
  3. stepfen

    stepfen Barracuda

    # of Dives: 100 - 199
    Location: Greece
    361
    160
    43
    @atdotde Are you a developer? If so, I'd like to thank you for this incredible piece of software. Well done!

    Now about the warning, the way it is written looks like it is something new and temporal (pending more testing). I mean a new user can't know if it has been there for ever or since the last update. That's why I asked.

    Maybe you could rephrase it to a more standard warning/disclaimer, but just by guessing how much effort the dev team is dedicating to support all the computers and user complains out there, I'd guess such request would be a very low priority.

    In any way, congratulations once more ! Keep up good work!
     
  4. theBro

    theBro Angel Fish

    28
    8
    3
    atdotde is the maintainer of the planning feature. IIRC the disclaimer has been there since the early days, so for a couple of years. We have done some benchmarking against other planning software and the results are in the ballpark of other software, at least normally. But naturally there might be some corner cases that produce interesting results. Maybe the disclaimer could be reworded, but it is there to remind people of the fact that deco algorithms are only an approximation of empiric tests, not exact science. Some people do get bent even when following dive tables, and some people don't even when they break them.
     

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