What is an efficient algorithm for finding the minimum of a parabola-shaped function? I have a continuous function f(x) that is bounded on the interval (0, N), where N is a large positive integer (~10,000,000). The function is shaped like an upwards-facing parabola, however, it is slightly skewed (so not exactly parabolic). I am able to calculate values of f(x), however it is quite computationally expensive to sample.
What are some possible algorithms for efficiently and accurately approximating the minimum value of this parabola-shaped function using the smallest number of iterations?

Ternary search is a simple algorithm to find the minimum (or maximum) of a unimodal function without using any derivative information. It proceeds by starting with some interval, and then recursively discards one-third of the interval until some tolerance is reached.
