[eigen] questions and remarks to automatic differentiation based on adol-c

[Christian Reinl <reinl@xxxxxxxxxxxxxxxxxxx>]

Dear developers of the Eigen library,


we tested your modules for automatic differentiation based on adol-c and 
found some (more ore less small) errors. Maybe that a responsible 
developer will appreciate this feedback and is able to easily fix it.

Thank you all very much for maintaining and further developing Eigen!


Best regards,

Christian Reinl


ERRORS:
______________________________________________________________________________________________________________________________________

A) Using the LU module:
--------------------------------------------------------------------
error message:
<PATH TO EIGEN>/Eigen/src/LU/LU.h:514: error: no matching function for 
call to ‘ei_isMuchSmallerThan(const adtl::adouble&, adtl::adouble&, 
const adtl::adouble&)’


B) Using the Choleskey module:
--------------------------------------------------------------------
there was missing something, too


C) in AdolcForward:
--------------------------------------------------------------------
1)..................................
in
template<> struct NumTraits<adtl::adouble>
{
typedef adtl::adouble Real;
typedef adtl::adouble NonInteger;
typedef adtl::adouble Nested;
enum {
....... (**)
};
};

" HasFloatingPoint = 1" is missing at (**)

2)..................................
The comment suggests (line 75)
#include <unsupported/Eigen/AdolcSupport>
but AdolCSupport does not exist.

______________________________________________________________________________________________________________________________________

--
Christian Reinl                       reinl@xxxxxxxxxxxxxxxxxxx
Simulation, Systems Optimization      Phone:  +49 (0) 6151-16-5212
and Robotics                          Fax:    +49 (0) 6151-16-6648
Technische Universitaet Darmstadt
Hochschulstr. 10
D-64289 Darmstadt, Germany            http://www.sim.tu-darmstadt.de