Lagrange polynomial interpolation

Lagrange polynomial interpolation

Description

Approx a point-defined function using Lagrange polinomial interpolation method

• Acknowledgements: This submission has inspired the following:; lagrange interpolation and derivative, Barycentric Lagrange Interpolating Polynomials and Lebesgue Constant, Lagrange Interpolator Polynomial, Piecewise Hermite Cubic Interpolation
• MATLAB release: MATLAB 5.2 (R10)

[steve xia]

 

[keene rolph]

The source code is very fantastic.it is good for research especially for mathematics purpose.

[oziel alcocer]

 

[t t]

beautiful,

[Sukant Gupta]

 

[sima asgari]

math

[Fahad Abbassi]

Man u r a king and matlab is your bitch!!

[Aleksey Rozsdobudko]

what did u write?????? It can write even a child!!!!
dont use such words as "for","while" and anything like that in the matlab cos it's STUPPIDNESS!!!!!!

[im einnor]

flawless program!

[bill cosby]

Thank you for a great program

[JJ LS]

Very Good

[T B]

Great job!!! Good work!

[STEFANO IANNARILLI]

THANK YOU VERY MUCH FOR IT.
I NEEDED FOR MY STUDYING

[frederico schultz]

muito obrigado...boa sorte

[Jev Jeg]

 

[Haroon Awais]

good work, but it is better to use Matlab "interp1" function.

[haris ahmad]

i am a student of electronics engr and hav to do numerical diff using lagrange

[Jose Garcia]

 

[John D'Errico]

Lagrange interpolation is one of those interpolation methods that beginning textbooks include, along the way to showing you some useful methods. I imagine the textbook authors want to show you some of the history of interpolation. The fact is, high order Lagrange interpolation of this ilk was a only ever a good idea BACK IN the time of Lagrange. There has actually been progress in knowledge since then. (Surprise!) This is a terribly poor choice of interpolation method today.

In general, splines or other methods like them (PCHIP) will be less likely to introduce interpolation artifacts, oscillations, etc. Splines will be FAR less sensitive to tiny amounts of noise than will a high order Lagrange.

Even if I choose to disregard the method it implements,
the code itself is poorly implemented. It is triply looped - totally unvectorized. Expect it to be slow and if you have a large number of points, it will take more memory than need be.

If you need to use an interpolation tool, start with interp1, spline, or pchip, or look to the splines toolbox for more choices.

[imran aslam]

 

[Arc .]

Very usefull - I need it for convertion to java code.

[hira manzoor]

 

[Pier Francesco Maria Gatti]

what is x? :D

[LAY Nary]

I don't know

[mahesh nair]

 

[Satya Sudhakar Yedlapalli]

Can be made as a basic matlab function

[sanjay zine]

 

[pamonz wank]

 

[Angela]

and what exactly do you have to give as input??

[naser Rashwan]

how to represent x, i represent the x as [1 0] but it did not give the right answer

[madinatul munawaroh]

anyone can give me example how to use it?
i need it for my study...

[Juan Camilo Medina]

Simple yet functional code. Thanks

[BobAlpha]

 

[Andrew]

To answer some of those questions here is an example of input:
x=linspace(-10,10,500);
lagrange(x,[x0,...,xn],[f(x0),...f(xn)])
where [x0,...,xn] is pseudo-code for representing the x values as an array and [f(x0),...,f(xn)]. Then try to plot that lagrange against the function you are interpolating and you should see the desired results.