def derivativeY(self,w,x,y,z):
        '''
        Evaluates the partial derivative with respect to y (the third argument)
        of the interpolated function at the given input.

        Parameters
        ----------
        w : np.array or float
            Real values to be evaluated in the interpolated function.
        x : np.array or float
            Real values to be evaluated in the interpolated function; must be
            the same size as w.
        y : np.array or float
            Real values to be evaluated in the interpolated function; must be
            the same size as w.
        z : np.array or float
            Real values to be evaluated in the interpolated function; must be
            the same size as w.

        Returns
        -------
        dfdy : np.array or float
            The derivative with respect to y of the interpolated function eval-
            uated at w,x,y,z: dfdy = f_y(w,x,y,z), with the same shape as inputs.
        '''
        wa = np.asarray(w)
        xa = np.asarray(x)
        ya = np.asarray(y)
        za = np.asarray(z)
        return (self._derY(wa.flatten(),xa.flatten(),ya.flatten(),za.flatten())).reshape(wa.shape)
Evaluates the partial derivative with respect to y (the third argument)
        of the interpolated function at the given input.

        Parameters
        ----------
        w : np.array or float
            Real values to be evaluated in the interpolated function.
        x : np.array or float
            Real values to be evaluated in the interpolated function; must be
            the same size as w.
        y : np.array or float
            Real values to be evaluated in the interpolated function; must be
            the same size as w.
        z : np.array or float
            Real values to be evaluated in the interpolated function; must be
            the same size as w.

        Returns
        -------
        dfdy : np.array or float
            The derivative with respect to y of the interpolated function eval-
            uated at w,x,y,z: dfdy = f_y(w,x,y,z), with the same shape as inputs.