A bound that corresponds to the minimal absolute function value.
The minimal of absolute function values.
Left bound
f(ax) or f(ax).fabs.fmin(T.max / 2).copysign(f(ax)).
Rifht bound
f(bx) or f(bx).fabs.fmin(T.max / 2).copysign(f(bx)).
Amount of target function calls.