Deprecated since version 4.0: The parabolic_turning_point function is deprecated and may be removed in version 4.1. Use sunkit_image.coalignment.parabolic_turning_point instead.

Find the location of the turning point for a parabola y(x) = ax^2 + bx + c, given input values y(-1), y(0), y(1). The maximum is located at x0 = -b / 2a. Assumes that the input array represents an equally spaced sampling at the locations y(-1), y(0) and y(1).


y (numpy.ndarray) – A one dimensional numpy array of shape “3” with entries that sample the parabola at “-1”, “0”, and “1”.


float – A float, the location of the parabola maximum.