RGBM Licensing?

GAP · 8th May 2006, 17:17

Quote: (Originally Posted by lizardland)

As for VPM when Eric Baker sent me an early copy of the code he told me it could be used freely provided it wasn't for a commercial venture. It would appear the license has since changed as there are now commercial products using VPM.

and different versions, Ross's VPM-BE, VR-3 VPM, Nautilus's VPM........

Greetings Kees

zbskii · 8th May 2006, 18:19

Cool, need some help? My thought was writing a deco program that let you compare several different algorithms, mostly for research purposes. Looks pretty simple, at least for VPM. By 'formal model' I'm assuming you mean to try and run formal logic validation?
-Brett

Quote: (Originally Posted by AD_ward9)

Only RGBM requires a fee, and that is only because their algorithm is not fully disclosed. That fact alone makes it impossible to formally verify that the implementation is correct. Bruce Wienke is the man to contact, and $4.5k seems to be the going rate to start with.

It is our intention to publish a RGBM formal model, which anyone can then challenge as being wrong. At the moment, there are so many differences between different "RGBM" implementations, we are having real difficulty validating our formal model. When we contacted Bruce Wienke to access the database of profiles he is building up we were denied access - we believe the reason is our formal model would have shown up the wide variation in RGBM implementations, rather than worries about loss of licence revenue. There appear to be a series of different RGBM algorithms in use, of different dates.

On the technical info, there is a fair bit on Bruce's site, and he is a co-author on a lot of scientific papers involving deco which you can find easily. However, there is no reference implementation.

Cheers,

Alex

rossh · 9th May 2006, 05:07

Quote: (Originally Posted by GAP)

and different versions, Ross's VPM-BE, VR-3 VPM, Nautilus's VPM........
Greetings Kees

The VPM model and revisions are clear and straight forward.

The original is VPM (now called A): this is the original model by Yount, Hoffman, adapted for use by Maiken, Baker and others. This is what the Nautilus program uses too. VPM original has some design errors in the way it is coded, and the VPM-B revision corrects these problems.

VPM-B is the model in widespread use today.

VPM-B/E is my extended version that gives deep divers an overlapped bubble / Buhlmann style plan that they often want to use. The VR3 attempts to emulate this version.

Notice how each revision has been given a unique designation.

The RGBM appears to morph all revisions under one designation, and its many pseudo implementations under the same name. I've said this before, the RGBM is a concept, a marketing brand name, a collection of different implementations, with little or no distinction made between these.

Regards

Genesis · 9th May 2006, 13:58

The biggest problem with RGBM is figuring out what you've got and how it works.

That sort of thing scares me. We're all guinea pigs to an extent regardless, but using a deco model that is entirely opaque is not on my "A" list.

Same problem with Cochran's implementation..... all hidden in a "black box".

GAP · 9th May 2006, 17:43

Hi Ross,
For the implementation on the desktop of RGBM there is only one up to date iterative RGBM implementation and that is GAP.

Perhaps I'll release the reference fortran executable in the future..... perhaps.

I'll include the RGBM version into gap in the future, although it is already there in the GAP-Lite version for every body to see.

People can mail me at hofwegen@gap-software.com for details about RGBM within reason

. Many customer of the GAP-Software products have done so but this is an open invitation to all people on this board.
I'll will not be draged into a flame war who's model is best, so lets keep it clean.

Greetings Kees

Quote: (Originally Posted by rossh)

The VPM model and revisions are clear and straight forward.

The original is VPM (now called A): this is the original model by Yount, Hoffman, adapted for use by Maiken, Baker and others. This is what the Nautilus program uses too. VPM original has some design errors in the way it is coded, and the VPM-B revision corrects these problems.

VPM-B is the model in widespread use today.

VPM-B/E is my extended version that gives deep divers an overlapped bubble / Buhlmann style plan that they often want to use. The VR3 attempts to emulate this version.

Notice how each revision has been given a unique designation.

The RGBM appears to morph all revisions under one designation, and its many pseudo implementations under the same name. I've said this before, the RGBM is a concept, a marketing brand name, a collection of different implementations, with little or no distinction made between these.

Regards

***schford*** · 9th May 2006, 18:36

Quote: (Originally Posted by GAP)

I'll will not be draged into a flame war who's model is best, so lets keep it clean.

Greetings Kees

Well said have a blob :-)

Now in a Texan accent...

folks could it get much better than this - we have two of the finest authors of deco software on the board lets make the most of their knowledge!

***caveseeker7*** · 9th May 2006, 18:49

Quote: (Originally Posted by schford)

... Texan accent ... two of the finest authors of deco software on the board ...

Texan accent? Deco software author? Let's not forget Decoweenie.

decoweenie · 9th May 2006, 19:25

Quote: (Originally Posted by caveseeker7)

Texan accent? Deco software author? Let's not forget Decoweenie.

My wife still have a strong southern accent, but no Texan accent on this boy...

Johan · 9th May 2006, 23:04

It seems to be common knowledge that the VPM algorithm is freely available but does anyone know:

Which is the reference implementation of VPM-B for rebreather divers?

As far as I know there is the original VPM-B code (Baker). This is straightforward code but it only appears to handle the OC case. Then there are CCR adaptions like Maikens code in VBA and Spaughs CCR adaption of Bakers VPM code in Fortran.

Initially it seems pretty straight forward to port the initial code to the CCR case just by calculating the gas fractions based on setpoint and depth. However, using rebreathers the air should be more humid (right?) so there should be more water vapor in the gas. Shouldn't this be taken into calculation considering the water vapor pressure already is a variable in the OC case? The second thing that may differ is how to use the Schreiner equation which is discussed HERE.

It seems like most people on this forum uses V-Planner but I dont know how it adapts the VPM-B model to CCR (or SCR for that case). Would be interesting to know since then other implementations can use the same approach and together build a better dive database. Maybe Ross can tell us? (btw not looking for the source code just the algorithm)

IMHO I think it would be nice to have a baseline reference implementation that has a set number of input values which produces a predictable deco plan for the CCR case just like the OC case. A bonus would of course be if the implementation would be in a more modern language such as C, Java or C#.

***jradomski*** · 10th May 2006, 04:41

Quote: (Originally Posted by Johan)

It seems to be common knowledge that the VPM algorithm is freely available but does anyone know:

Which is the reference implementation of VPM-B for rebreather divers?

As far as I know there is the original VPM-B code (Baker). This is straightforward code but it only appears to handle the OC case. Then there are CCR adaptions like Maikens code in VBA and Spaughs CCR adaption of Bakers VPM code in Fortran.

Initially it seems pretty straight forward to port the initial code to the CCR case just by calculating the gas fractions based on setpoint and depth. However, using rebreathers the air should be more humid (right?) so there should be more water vapor in the gas. Shouldn't this be taken into calculation considering the water vapor pressure already is a variable in the OC case? The second thing that may differ is how to use the Schreiner equation which is discussed HERE.

It seems like most people on this forum uses V-Planner but I dont know how it adapts the VPM-B model to CCR (or SCR for that case). Would be interesting to know since then other implementations can use the same approach and together build a better dive database. Maybe Ross can tell us? (btw not looking for the source code just the algorithm)

IMHO I think it would be nice to have a baseline reference implementation that has a set number of input values which produces a predictable deco plan for the CCR case just like the OC case. A bonus would of course be if the implementation would be in a more modern language such as C, Java or C#.

actually no, once inside the lungs the gas reaches 100% humidity.. 100% is 100% no matter how you cook it (on a CCR it just reaches this before it enters your body) .. Ther are some variations in the RQ numbers used by modellers but they make only a slight difference..

when you are on OC the inspired fractions (all gases) are less than the gas in the tank because of the addition of WVP.. On a CCR theoritically the PO2 should be correct based on measurements and only the inerts are reduced..but then again sensor accuracy is +/- 1% anyway

but either way variations in WVP only has small effects on the deco schedules.. There are 3 common RQ numbers, schreiner, buhlman and the us navy.. I user the Navy numbers as they are more conservatibe than buhlmans numbers but still only have a small effect..

8th May 2006, 17:17	#11 (permalink)
GAP RebreatherWorld Sponsor Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Aug 2005 Location: the Netherlands, heerhugoward Posts: 26	Re: RGBM Licensing? Quote: (Originally Posted by lizardland) As for VPM when Eric Baker sent me an early copy of the code he told me it could be used freely provided it wasn't for a commercial venture. It would appear the license has since changed as there are now commercial products using VPM. and different versions, Ross's VPM-BE, VR-3 VPM, Nautilus's VPM........ Greetings Kees __________________
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8th May 2006, 18:19	#12 (permalink)
zbskii I have a diving problem. Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Dec 2005 Location: Portland, OR Posts: 134	Re: RGBM Licensing? Cool, need some help? My thought was writing a deco program that let you compare several different algorithms, mostly for research purposes. Looks pretty simple, at least for VPM. By 'formal model' I'm assuming you mean to try and run formal logic validation? -Brett Quote: (Originally Posted by AD_ward9) Only RGBM requires a fee, and that is only because their algorithm is not fully disclosed. That fact alone makes it impossible to formally verify that the implementation is correct. Bruce Wienke is the man to contact, and $4.5k seems to be the going rate to start with. It is our intention to publish a RGBM formal model, which anyone can then challenge as being wrong. At the moment, there are so many differences between different "RGBM" implementations, we are having real difficulty validating our formal model. When we contacted Bruce Wienke to access the database of profiles he is building up we were denied access - we believe the reason is our formal model would have shown up the wide variation in RGBM implementations, rather than worries about loss of licence revenue. There appear to be a series of different RGBM algorithms in use, of different dates. On the technical info, there is a fair bit on Bruce's site, and he is a co-author on a lot of scientific papers involving deco which you can find easily. However, there is no reference implementation. Cheers, Alex
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9th May 2006, 05:07	#13 (permalink)
rossh Custom Title Allowed! Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jul 2005 Location: Canada Posts: 106	Re: RGBM Licensing? Quote: (Originally Posted by GAP) and different versions, Ross's VPM-BE, VR-3 VPM, Nautilus's VPM........ Greetings Kees The VPM model and revisions are clear and straight forward. The original is VPM (now called A): this is the original model by Yount, Hoffman, adapted for use by Maiken, Baker and others. This is what the Nautilus program uses too. VPM original has some design errors in the way it is coded, and the VPM-B revision corrects these problems. VPM-B is the model in widespread use today. VPM-B/E is my extended version that gives deep divers an overlapped bubble / Buhlmann style plan that they often want to use. The VR3 attempts to emulate this version. Notice how each revision has been given a unique designation. The RGBM appears to morph all revisions under one designation, and its many pseudo implementations under the same name. I've said this before, the RGBM is a concept, a marketing brand name, a collection of different implementations, with little or no distinction made between these. Regards __________________ Regards, Ross Hemingway V-Planner VPM-B Nitrox Trimix CCR Deco planning for Technical Divers www.v-planner.com Last edited by rossh : 9th May 2006 at 08:35.
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9th May 2006, 13:58	#14 (permalink)
Genesis Bubbless Box of Death Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Oct 2005 Location: Sunny Florida Posts: 1,394	Re: RGBM Licensing? The biggest problem with RGBM is figuring out what you've got and how it works. That sort of thing scares me. We're all guinea pigs to an extent regardless, but using a deco model that is entirely opaque is not on my "A" list. Same problem with Cochran's implementation..... all hidden in a "black box". __________________ "A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American." http://www.denninger.net http://www.diversunion.org/liability.htm - Fix the Diving Cert racket
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9th May 2006, 17:43	#15 (permalink)
GAP RebreatherWorld Sponsor Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Aug 2005 Location: the Netherlands, heerhugoward Posts: 26	Re: RGBM Licensing? Hi Ross, For the implementation on the desktop of RGBM there is only one up to date iterative RGBM implementation and that is GAP. Perhaps I'll release the reference fortran executable in the future..... perhaps. I'll include the RGBM version into gap in the future, although it is already there in the GAP-Lite version for every body to see. People can mail me at hofwegen@gap-software.com for details about RGBM within reason. Many customer of the GAP-Software products have done so but this is an open invitation to all people on this board. I'll will not be draged into a flame war who's model is best, so lets keep it clean. Greetings Kees Quote: (Originally Posted by rossh) The VPM model and revisions are clear and straight forward. The original is VPM (now called A): this is the original model by Yount, Hoffman, adapted for use by Maiken, Baker and others. This is what the Nautilus program uses too. VPM original has some design errors in the way it is coded, and the VPM-B revision corrects these problems. VPM-B is the model in widespread use today. VPM-B/E is my extended version that gives deep divers an overlapped bubble / Buhlmann style plan that they often want to use. The VR3 attempts to emulate this version. Notice how each revision has been given a unique designation. The RGBM appears to morph all revisions under one designation, and its many pseudo implementations under the same name. I've said this before, the RGBM is a concept, a marketing brand name, a collection of different implementations, with little or no distinction made between these. Regards __________________
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9th May 2006, 18:36	#16 (permalink)
*schford* Despotic Overlord Current Rebreather/s: Megalodon Sport Kiss Other Rebreather/s: Join Date: Jan 2005 Location: London, UK Posts: 3,671	Re: RGBM Licensing? Quote: (Originally Posted by GAP) I'll will not be draged into a flame war who's model is best, so lets keep it clean. Greetings Kees Well said have a blob :-) Now in a Texan accent... folks could it get much better than this - we have two of the finest authors of deco software on the board lets make the most of their knowledge! __________________ Bailout and Kit Management account for Murphy's Law The only bad question is one you did not ask and later wish you had. Use of Rebreather World is subject to the Rebreather World Terms & Conditions of Use
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9th May 2006, 18:49	#17 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,402	Re: RGBM Licensing? Quote: (Originally Posted by schford) ... Texan accent ... two of the finest authors of deco software on the board ... Texan accent? Deco software author? Let's not forget Decoweenie. __________________ Cheers Stefan "It is still a good day if you are on the green side of the grass! Su amigo Roberto!" Sponsor Lou in Race For Life!
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9th May 2006, 19:25	#18 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,510	Re: RGBM Licensing? Quote: (Originally Posted by caveseeker7) Texan accent? Deco software author? Let's not forget Decoweenie. My wife still have a strong southern accent, but no Texan accent on this boy...
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9th May 2006, 23:04	#19 (permalink)
Johan New Member Current Rebreather/s: Evolution Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: London Posts: 15	Re: RGBM Licensing? It seems to be common knowledge that the VPM algorithm is freely available but does anyone know: Which is the reference implementation of VPM-B for rebreather divers? As far as I know there is the original VPM-B code (Baker). This is straightforward code but it only appears to handle the OC case. Then there are CCR adaptions like Maikens code in VBA and Spaughs CCR adaption of Bakers VPM code in Fortran. Initially it seems pretty straight forward to port the initial code to the CCR case just by calculating the gas fractions based on setpoint and depth. However, using rebreathers the air should be more humid (right?) so there should be more water vapor in the gas. Shouldn't this be taken into calculation considering the water vapor pressure already is a variable in the OC case? The second thing that may differ is how to use the Schreiner equation which is discussed HERE. It seems like most people on this forum uses V-Planner but I dont know how it adapts the VPM-B model to CCR (or SCR for that case). Would be interesting to know since then other implementations can use the same approach and together build a better dive database. Maybe Ross can tell us? (btw not looking for the source code just the algorithm) IMHO I think it would be nice to have a baseline reference implementation that has a set number of input values which produces a predictable deco plan for the CCR case just like the OC case. A bonus would of course be if the implementation would be in a more modern language such as C, Java or C#. __________________ http://www.tacticaldiving.com
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10th May 2006, 04:41	#20 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,869	Re: RGBM Licensing? Quote: (Originally Posted by Johan) It seems to be common knowledge that the VPM algorithm is freely available but does anyone know: Which is the reference implementation of VPM-B for rebreather divers? As far as I know there is the original VPM-B code (Baker). This is straightforward code but it only appears to handle the OC case. Then there are CCR adaptions like Maikens code in VBA and Spaughs CCR adaption of Bakers VPM code in Fortran. Initially it seems pretty straight forward to port the initial code to the CCR case just by calculating the gas fractions based on setpoint and depth. However, using rebreathers the air should be more humid (right?) so there should be more water vapor in the gas. Shouldn't this be taken into calculation considering the water vapor pressure already is a variable in the OC case? The second thing that may differ is how to use the Schreiner equation which is discussed HERE. It seems like most people on this forum uses V-Planner but I dont know how it adapts the VPM-B model to CCR (or SCR for that case). Would be interesting to know since then other implementations can use the same approach and together build a better dive database. Maybe Ross can tell us? (btw not looking for the source code just the algorithm) IMHO I think it would be nice to have a baseline reference implementation that has a set number of input values which produces a predictable deco plan for the CCR case just like the OC case. A bonus would of course be if the implementation would be in a more modern language such as C, Java or C#. actually no, once inside the lungs the gas reaches 100% humidity.. 100% is 100% no matter how you cook it (on a CCR it just reaches this before it enters your body) .. Ther are some variations in the RQ numbers used by modellers but they make only a slight difference.. when you are on OC the inspired fractions (all gases) are less than the gas in the tank because of the addition of WVP.. On a CCR theoritically the PO2 should be correct based on measurements and only the inerts are reduced..but then again sensor accuracy is +/- 1% anyway but either way variations in WVP only has small effects on the deco schedules.. There are 3 common RQ numbers, schreiner, buhlman and the us navy.. I user the Navy numbers as they are more conservatibe than buhlmans numbers but still only have a small effect.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 10th May 2006 at 04:43.
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