From: Benoit Daloze <eregontp@...>
Date: 2010-05-14T03:13:51+09:00
Subject: Re: In Ruby, can the coerce() method know what operator it is th

On 13 May 2010 17:43:24 UTC+2, Colin Bartlett <colinb2r@googlemail.com> wrote:
> I wish I'd known about this
>  http://github.com/eregon/math/blob/master/math/polynomial.rb
> earlier this year: including differentiation _and_ integration!
> I was using polynomials to form weighted sums of discrete and
> continuous actuarial functions, so I needed integration of the
> polynomials.

You're very welcome to fork and use my code :)

> I couldn't find a polynomial.evaluate method, but polynomial.run(n)
> seems to give the numerical value of the polynomial for x == n: is
> that right?

Yes, #evaluate is bit long for a simple method like that.
Note it's also aliased to #& for very lazy people like me. So
Polynomial.new(...) & 4

> ### def -@(); @coef.map! { |c| -c }; end
> q = Polynomial.new( 2, 3, 1 )
> p q #=>   2x^2 + 3x + 1
> -q
> p q #=> - 2x^2 - 3x - 1
>
> If you don't mind me asking, what was the reason for #- changing the
> polynomial to its negative as opposed to returning a new polynomial
> which is the negative of the original polynomial?

Thanks for pointing me out, is just some residual from a long time,
when I didn't know yet about how ruby objects are never duplicated.
I supposed I simplified it later, without seeing this error.
(and I never used -P(x))

So now that's updated :)

I'm also working on symbolic, if you're interested in this kind of maths.

Regards,
B.D.