Projected Gauss Seidel patent and other physics patents

[Julio Jerez]

if in Newton you did the same or similar but nobody know about it that's not public domain knowledge i guess.

Well I am solving systems that can be as high as 16000 x 16000 you think I am doing magically? The proof is there and the Newton engine has been around long before this claim.

It looks like that you have misunderstood what im trying to say and im going to try to be clearer here. Im _not_ in favour of patents, however there is a law, if somebody applies for a patent that laws applies if we like it or not. So what im interested it's not if many other people did the same or better in their secret room given that i have no doubts about it. But im more interested to see if it possible to show that at the moment of the application there was sufficient available information (papers/code) in order t invalidate the "invention"

Then you am I agree. I just found the claim very disingenuous and I still believe it is public knowledge.

given that you seems so good at it i would advice you to do also some critical analysis of your writing style;)

Well you know what they say old dogs do not learn new tricks. I am just happy I can barely communicate. this is why I do not write novels.

wasn't in an incremental LU/cholesky factorization done in O(n^2)?

well the claim is no so, is only apply if you can sort the row in perfect order when row are to be remove the incremental factorization has to be thrown out. And you get the same o(n3) factorization.

I think you are right it is about the patent so maybe you am I agree. We were just discussing the details of what makes the patent legitimate.

[Antonio Martini]

if in Newton you did the same or similar but nobody know about it that's not public domain knowledge i guess.

Well I am solving systems that can be as high as 16000 x 16000 you think I am doing magically? The proof is there and the Newton engine has been around long before this claim.

the fact that you can solve a problem of similar/equal size at the same speed doesn't invalidate the patent claim. You may be reaching similar or even better performances by using a different method not publicly available. It's like concluding for the same cause given the same observed effect. It seems logically fallacious to me.
So unless you published the method somewhere it may not be that easy. . However i stress this again, i am not an expert about patents and related legislation. it would be interesting to hear other people opinions.

well the claim is no so, is only apply if you can sort the row in perfect order when row are to be remove the incremental factorization has to be thrown out. And you get the same o(n3) factorization.

as i said i wrote that stuff many years ago however i dont remember of throwing away the factorization. So i guess i was somehow doing the perfect ordering thing you mention whatever it may be. It would be interesting to see if ODE is discarding the factorization at some point in the direct solver. Or if we are lucky and Russ is reading this, he might tell us directly. The mathengine patent is his after all:)

[Julio Jerez]

as i said i wrote that stuff many years ago however i dont remember of throwing away the factorization. So i guess i was somehow doing the perfect ordering thing you mention whatever it may be. It would be interesting to see if ODE is discarding the factorization at some point in the direct solver. Or if we are lucky and Russ is reading this, he might tell us directly. The mathengine patent is his after all:)

I do not really care for Gauss Seidle or Pivoting Lemkel/Danzig method although I do question the claims.

I thought we finish this conversation with the last post but if you insist.
I am more than happy to explain to you why the factorization most be throwing out when you remove a row. (I hope you understand my broken English).

Say you are adding the N active variable from the inactive set and it just happens this new active variable forces another active variable to the inactive set.
It just happens that the forced out variable could be anywhere in the array.
Since the construction of each row is an n^2 order, and you have a probability of n/2 of the variable to been anywhere on the active set. You end up with
n/2 rows of ( n *n ) operation for re-factorizations.
the only thing the incremental factorization do is that is reduces the constant in front of the 0(n4) by a significat value.
you can probably get a factor of 2 or 3 speed up but never one order of magnitud reduction.

And since the majority of the non-zero elements of the lower diagonal matrix are by the end of the array. The lower haft of the factorization carry almost full n * n *n cost statistically. So yes I say with 100% of certainty Baraff implementation of dazing is a precise O(n4) average case
This is not a thing that is a matter of a person opinion this is an absolute fact.
If ODE or your implementation is not doing it that way then my apologies that is a patent able claim if it works. Or it is just wrong.

[Julio Jerez]

My post of this thread had been answered to other post.

I see that some of the other post had been edited and other had been removed after I replied Leaving just my answer dangling like a complete idiot out of context.
This is not the first time this had happens here.
I cannot do that except on the very last post.

Thank you very much.

[Erwin Coumans]

I appreciate and respect all contributions. Therefore no post have been removed, only split.

Antonio asked to have the topic split into patent-related posts and pgs-impulse comparison posts. This is what I did. See this post:
http://www.continuousphysics.com/Bullet ... .php?t=208

I removed 2 lines, because they linked the two together.
Those lines where:
1) the split request of Antonio, because it had be executed
2) a comment from Erin Catto to Jerez that linked the two topics together, which don't make sense anymore after splitting.

Sorry for the confusion of the split, there were no intension to remove any comments.