Function rgsl::interpolation::eval_deriv2_e

pub fn eval_deriv2_e(interp: &Interp, xa: &[f64], ya: &[f64], x: f64, acc: &mut InterpAccel, d2: &mut f64) -> Value

This function returns the second derivative d2 of an interpolated function for a given point x, using the interpolation object interp, data arrays xa and ya and the accelerator acc.