Now we are going to use the Function Wizard to create a function with a matrix argument.
Add a new argument Z and use the matrix tool to change it to a 2-dimensional argument. (Alternatively, you can use Ctrl+2 as a short-cut.)
Fill in the fields of Z as follows:
Type: Double Name: Z Description: Matrix of Z values
Add the remaining arguments, as shown below. You may find it convenient to use the copy and paste argument commands to enter InterpY.
Type: Double Name: InterpX Description: X value at interpolation point
Type: Double Name: InterpY Description: Y value at interpolation point
When you've finished, the Function Wizard should look like this:
Click on the OK button to dismiss the Wizard and update the source code.