
Hi,
I tried to execute your example, but the calculation of the gradient failed. Even when I set var func = TermBuilder.Exp(x) the derivation is not correct and even not defined for negative values of x.
What's wrong? Thanks for your answer!
Enza


Coordinator
Apr 3, 2011 at 8:15 PM

Which version?
I had a problem with e^x once and I fixed it after 0.2 was released. If it was 0.2, then it was fixed in 0.3.
Have fun!!



Thank you very much! I used version 0.2, in 0.3 it works fine.
Is it also possible to differentiate functions that are not given in an analytical form?
Enza


Coordinator
Apr 6, 2011 at 7:06 AM

Right now it is not.
I do plan to add the ability to provide userdefined unary or binary functions. The user will provide a delegate to compute the value and the partial derivatives. Then the user will be able to compose his terms out of these functions and differentiate the
terms.
I have a question myself  what is your usage scenario? What are you trying to optimize?
Alex.



Hi Alex,
I'm working on a mesh optimization algorithm that needs the derivatives of my geometry functions. Right now I'm using an AitkenNevillealgorithm with devided central differences to calculate them (found in the book Numerical Recipes), but it really slows
down my algorithm. So I wondered if there is some code that can do it much faster. I looked around and found many libraries for numerical integration but no C#libraries for numerical derivation.
A few days ago, I discoverd http://ooot.codeplex.com/. It looks very interesting because the derivatives can be either provided by the user or be calculated by the algorithm. But I hadn't still the time to try those
algorithms with my functions.
Best regards,
Enza


Coordinator
Apr 8, 2011 at 1:35 PM

So we both work on the same subject  geometric modelling. Good luck!
I also encountered OOOT. As you can see, it's one of my "related projects" in AutoDiff homepage.
Alex.

