[R] From polynomial to function
Karl Ove Hufthammer
karl at huftis.org
Wed Jan 12 10:47:31 CET 2011
Alaios wrote:
> x<-legendre.polynomials(2)[[3]]
>> x
> -0.5 + 1.5*x^2
>
>> str(x)
> Class 'polynomial' num [1:3] -0.5 0 1.5
>
> As you can see from the code above str(x) returns that x is of class
> polynomial. I want to use that polynomial as a function. The reason for
> that is that I would be grateful if I can feed that kind of function
> inside integrate(f,lower=,upper=)
You can use the ‘as.function’ function. But if you’re just going to
integrate the polynomial anyway, why don’t you just use the ‘integral’
function? It’s much more accurate than using numerical integration.
BTW, to see which functions handle ‘polynomial’ objects, use
methods(class="polynomial")
Output:
[1] as.character.polynomial* as.function.polynomial* coef.polynomial*
[4] deriv.polynomial* GCD.polynomial* integral.polynomial*
[7] LCM.polynomial* lines.polynomial* Math.polynomial*
[10] Ops.polynomial* plot.polynomial* points.polynomial*
[13] predict.polynomial* print.polynomial* solve.polynomial*
[16] summary.polynomial* Summary.polynomial*
--
Karl Ove Hufthammer
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