From: Simon Strandgaard <neoneye@...>
Date: 2004-11-11T03:51:56+09:00
Subject: Re: [ann] symbol solver.. early experiments

On Tuesday 09 November 2004 23:13, Josef 'Jupp' Schugt wrote:
[snip]
> Adding is then done by list member:
> [4 + 46, 3 + 1, 2 + 0, 1 + 7] = [46, 4, 2, 8]
> which represents
> 8x**3 + 2x**2 + 4x + 46
[snip diff, mul]

An array per variable, maybe something ala

{
  :x = [4, 3, 2],
  :y = [9, 6]
}

That should deal with most polynomias.

At the moment I have represented polynomias.. as an ast.
x^4+x^3+x^2+y^9+y^6
would in ast form.. be:

add(add(add(add(
exp(mul(4, log(x))),
exp(mul(3, log(x)))),
exp(mul(2, log(x)))), 
exp(mul(9, log(y)))), 
exp(mul(6, log(y))))

maybe I should make a Polynomium class?
so it would become

add(poly(4,3,2), poly(9,6))

(I had not thought about a polynomium class)

> If you take a close look at the indices you see that all ci are the sum
> of all products of aj and bk where j+k=i. The implementation in Ruby is
> straightforward.

Thanks.

--
Simon Strandgaard