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... 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.... 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.