-----Original Message----- From: Boost-users [mailto:boost-users-bounces@lists.boost.org] On Behalf Of John Maddock Sent: 09 December 2014 12:58 To: boost-users@lists.boost.org Subject: Re: [Boost-users] [Math] advice using brent_find_minima()
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/interna... 1/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/interna... 1/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 ;-)
There is an example http://www.boost.org/doc/libs/1_57_0/libs/math/example/root_finding_example.... that you might find helpful. Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830