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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] AutoDiffScalar
- From: Björn Piltz <bjornpiltz@xxxxxxxxxxxxxx>
- Date: Tue, 20 Oct 2009 13:58:59 +0200
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I've done some more testing and got the class to work for
fixed/dynamic/sparse cases 1st and 2nd derivatives.
There are some minor bugs in the code and I had to rewrite
CompressedStorage to handle non-POD data types(evil memcpy's).
You are obviously still working on the code, so I was wondering how I
should submit any fixes.
Clone the repository and submit a patch queue/pull request?
There is also the question of performance. For second and higher order
derivatives There is a need to differentiate the type Scalar from the
underlying primitive type. let's call it Real for now.
E.g.
typedef AutoDiffScalar<Matrix<double, Dynamic, 1> > D1;
typedef AutoDiffScalar<Matrix<Fad1 , Dynamic, 1> > D2;
D1::Scalar == double
D1::Real == double
D2::Scalar == D1
D2::Real == double
Then the overloads should be
AutoDiffScalar OP AutoDiffScalar::Real
instead of
AutoDiffScalar OP AutoDiffScalar::Scalar
That should lead to resize()/zero() being called significantly less often.