Interpolate cube values from all elements of an structure array of
all cube fieldnames.
This function should be called from getValue method of Surface class
which handles all input and ouput data.
Please note that axis values needs to be sorted.
Input and output variables:
- struct: structure with the following fields (struct)
- id: scenario ID (string)
- cube: volatility cube (one volatility value per x,y,z coordinate) (NDArray)
- x_axis: sorted vector of x-axis values (NDArray)
- y_axis: sorted vector of y-axis values (NDArray)
- z_axis: sorted vector of z-axis values (NDArray)
- xx: x coordinate used for interpolation of cube value
- yy: y coordinate used for interpolation of cube value
- zz: z coordinate used for interpolation of cube value (scalar or vector)
- retvec: return vector of scenario dependent interpolated volatility values (NDArray)