Polynomiale Least Square

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Polynomiale Least Square

cheikh diabang
Hello. I would like to write gambas code which determines the polynomial of a set of x, y coordinates. Is there anyone who has used it to help me please.
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Re: Polynomiale Least Square

Tobias Boege-2
On Tue, 18 Apr 2017, cheikh diabang wrote:
> Hello. I would like to write gambas code which determines the polynomial of a set of x, y coordinates. Is there anyone who has used it to help me please.

If your polynomial has real or complex coefficients you can use gb.gsl's [1]
Polynomial class. But while the documentation says arithmetic operators are
overloaded in gb.gsl, this isn't entirely true for polynomials. In particular
multiplication of polynomials is not supported. You have to implement that
yourself using the array accessors. Addition and multiplication of polynomials
is all you need for Lagrange polynomials [2] which solve your interpolation
problem. I have done it before, it's straightforward.

Regards,
Tobi

[1] http://gambaswiki.org/wiki/comp/gb.gsl
[2] https://en.wikipedia.org/wiki/Lagrange_polynomial

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Re: Polynomiale Least Square

cheikh diabang
Thank you Tobias.

I've seen the explanation, I'm going. Next time

________________________________
De : Tobias Boege <[hidden email]>
Envoyé : mardi 18 avril 2017 09:55
À : mailing list for gambas users
Objet : Re: [Gambas-user] Polynomiale Least Square

On Tue, 18 Apr 2017, cheikh diabang wrote:
> Hello. I would like to write gambas code which determines the polynomial of a set of x, y coordinates. Is there anyone who has used it to help me please.

If your polynomial has real or complex coefficients you can use gb.gsl's [1]
Polynomial class. But while the documentation says arithmetic operators are
overloaded in gb.gsl, this isn't entirely true for polynomials. In particular
multiplication of polynomials is not supported. You have to implement that
yourself using the array accessors. Addition and multiplication of polynomials
is all you need for Lagrange polynomials [2] which solve your interpolation
problem. I have done it before, it's straightforward.

Regards,
Tobi

[1] http://gambaswiki.org/wiki/comp/gb.gsl
Gambas Documentation - /comp/gb.gsl - gambaswiki.org<http://gambaswiki.org/wiki/comp/gb.gsl>
gambaswiki.org
gb.gsl. This component aims at providing most of the features of the Gnu Scientific Library. At the moment, it adds support for complex numbers, vectors, matrices and ...


[2] https://en.wikipedia.org/wiki/Lagrange_polynomial
Lagrange polynomial - Wikipedia<https://en.wikipedia.org/wiki/Lagrange_polynomial>
en.wikipedia.org
In numerical analysis, Lagrange polynomials are used for polynomial interpolation. For a given set of distinct points and numbers , the Lagrange polynomial is the ...



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