As a side note:
Some time ago I also implemented a Gauss integration with Legendre Polynomials and found that the
Goloub-Welsh method is not very effective for the calculaton of the roots. I implemented another
method (first guess based on heuristic formula followed by Newton like iteration), which usually
outperformed the Goloub method. If this is of interest, I could submit the code, which is template
based and should allow for arbitrary precision (I tested up to Quad precision only, though)
On 25/08/14 10:38, Pavel Holoborodko wrote:
This module would be of high value indeed.
Especially in combination with multi-precision support.
Then Eigen would have full spectrum of classic numerical integration methods (and in arbitrary
(As far as I know, adaptive Guass-Kronrod is being developed as another module for Eigen as well)
On Mon, Aug 25, 2014 at 5:19 PM, Manuel Yguel <manuel.yguel@xxxxxxxxx
I think it is a nice thing to have, I am interested to take a look at it.
Dr. Ing. Manuel Yguel
Porteur du projet StraTagGem
36, rue de l'Université
Tel: +33 9 73 52 86 75 <tel:%2B33%20%209%2073%2052%2086%2075>
Mobile: +33 6 59 59 17 30 <tel:%2B33%20%206%2059%2059%2017%2030>
On 08/25/2014 10:16 AM, Roman Pascal Schärer wrote:
Dear Eigen developers and users,
we developed a small C++ package for the computation of orthogonal polynomials (OPQ++) as an
unsupported module inside Eigen for our own needs.
The main goal of this package is to provide methods to compute an orthogonal set of
polynomials for a given weight function. This has been realised with the modified Chebyshev
algorithm, which computes the recurrence coefficients of the polynomials. This algorithm
makes use of the moments of the weight function, which in general need to be computed using
some numerical integration method. For now we provide our own implementations of quadrature
formulas (e.q. Gaussian quadratures). With the obtained recurrence coefficients the nodes and
weights of a Gaussian quadrature formula for the weight function can be easily computed using
e.g. the Golub-Welsch algorithm.
Since this package could be easily integrated in the Eigen library, I’d like to ask if there
is interest for such a module to be made public. Since it is a rather small module, it could
e.g. also be integrated in the “Polynomials Module”.
If such interest exists, we would be open for suggestions regarding the API and the
implementation of more features such as multi-precision floating point number support etc.
Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)
Institut für Methodik der Fernerkundung | Experimentelle Verfahren | Münchener Str 20| 82234 Weßling
Dr. Claas H. Köhler
Telefon 08153 28-1274 | Telefax 08153 28-1337 | claas.koehler@xxxxxxwww.DLR.de/EOC