The ‘cubic’ method in 'griddedInterpolant' is the same as ‘v5cubic’ in 'interp1':
In addition to this documentation, there is a brief explanation of 'v5cubic' on Cleve's blog (under 'Interp1'):
The 'cubic' method of 'griddedInterpolant' is a local C1 piecewise cubic Hermite interpolation method where the slope at a grid point x(n) is the mean of neighboring values y(n-1) and y(n+1).
This method does not support user-defined derivatives and requires the abscissa x to be equally spaced.
