One dimensional interpolation.
x A real vector sepcifying the points at which the function values are known.
y A real vector, containing the values of the function to be interpolated at the points defined by x .
xn A real array, containing the values of x at which the interpolated values of the function are needed.
interpolator The second output of a prior call to interp1 .
option 'nn' for nearest neigbor interpolation, 'linear' for linear interpolation, 'cubic' for piecewise cubic interpolation, and 'spline' for spline interpolation. The default value of option is 'cubic' .
yn The interpolated values of the function at the points specified by xn .
interpolator An object that can be used subsequently to interpolate the same function at other points by using the last form of call to interp1 .