John Maddock
I'd like to find the root of a function f (find x such that f(x) =
0).
Should I pass abs( f ) to brent_find_minima()?
No: that's a truly lousy method for finding the root.
If you have one or more derivatives of f then use newton_raphson_iterate or halley_iterate from
http://www.boost.org/doc/libs/1_57_0/libs/math/doc/html/math_toolkit/inte rnals1/roots.html
Otherwise use toms748_solve or bracket_and_solve_root from
http://www.boost.org/doc/libs/1_57_0/libs/math/doc/html/math_toolkit/inte rnals1/roots2.html.
Note that the latter of these two calls the former, which happens to be asymptotically optimal if you have no derivative information.
And no, we don't have examples for these as they're "details" that aren't officially part of the library yet. However, we really should do something about that as the code has actually been stable for millennia now
HTH, John.
OK, now I got it! You have brent algorithm for finding the minima, but not brent algorithm for finding the root. I don't have derivative for f, so how does toms748_solve compare to [1]? Regards [1] http://en.wikipedia.org/wiki/Brent%27s_method