The Interpolation function calculates the linear or cubicspline interpolated Y value based on a desired X value and a range of known X and Y values. The interpolation function can be used in conjunction with the various option models.
Interpolation 
(InterpolationType, Xrange, Yrange, ValueX) 
Argument 
Description 
InterpolationType 
Alphanumeric value indicating the interpolation type or model: Linear = 0 or "L" (case insensitive) Cubic Spline = 1 or "C" (case insensitive) 
Xrange 
The range of ascending and unique (nonduplicate) known X values. The size of the array, i.e. the number of values within it, must be the same as the Yrange array. 
Yrange 
The range of known Y values, where the size of the array must be the same as the Xrange. 
ValueX 
The input value for the X coordinate whereby a Y value is desired and the return value of the function. 
Example
Example: Linear and Cubic Spline Interpolation Calculate the linear and cubic spline interpolation and graph the results give the following table of known X and Y values at the Desired X values below. So, 
Input 

Output 

Known X 
Known Y 

Desired X 
Linear Interpolation 
Cubic Spline Interpolation 
0.500 
3.250 

0.500 
3.250 
3.250 
1.000 
3.625 

1.500 
3.792 
3.865 
2.500 
4.125 

2.500 
4.125 
4.125 
4.750 
4.375 

3.500 
4.236 
4.426 
6.250 
3.250 

4.500 
4.347 
4.464 
9.500 
3.125 

5.500 
3.813 
3.853 



6.500 
3.240 
3.099 



7.500 
3.202 
2.807 



8.500 
3.163 
2.875 



9.500 
3.125 
3.125 
For a further example on this model see the included Excel Template located in the root directory of the addin. This example can be accessed through the Utility Template menu item after the addin has been installed properly.
A list of all of the possible Error Messages is included for convenience.