A reduced multicubic database interpolation method is provided. The interpolation
method is designed to map a function and its associated argument into an interpolated
value using a database of points. The database is searched to locate an interpolation
cell that includes the function argument. The interpolation cell is used to transform
the function argument to reflect translation of the interpolation cell to a unit
cell. The interpolated value is then generated as a cubic function using the data
points that correspond to vertices of the unit cell. All of the derivatives in
the cubic function are simple and the interpolation accuracy order is higher than first-order.