dawn@0: % [y,idx] = minparabolic(x) - locate minima using parabolic interpolation
dawn@0: %
dawn@0: %  x: input vector
dawn@0: %  y: same as x, with local minima replaced by interpolated minima
dawn@0: %  idx: position of interpolated minima (fractionary)
dawn@0: %
dawn@0: % At each local minimum of x, that sample and its neighbors are used to
dawn@0: % determine a parabola.  The minimum of the parabola is used as the new
dawn@0: % minimum value, the abscissa of the minimum is used as its position.