Root function

["lauradiara\ at libero\ dot it" <lauradiara at libero dot it>]

Hi,

I'd like to write a function which finds all the roots of a funcion y=f(x)
provided by the user.

I have read the chapter one dimensional root finding: I have some questions.

The concept expressed is that you use root bracketing or root polishing: with
the first you have to provide an initial intervalwitha root inside, while with
the second you have to provide a guess root.

The first question is: both metods find only a root: if the function has more
roots what happen?

The second question is that the initial condition (guess or interval with a
root) is not simple, it's difficult to provide a good value.

All the examples are quite simple with a function provided athe start and not
inserted by the user: so the guess or the interval is simple. But in the real
applications, what can you do?

I think there is a solution, otherwise the functions in gsl_roots,h are not
usable in real situations.


Can you give me some advice?


Thanks


--Laura