MATLAB: Adaptive Lookup Tables – is the data used for updating the table interpolated

Question

Hello everybody,

I'm using the Adaptive Lookup Tables for estimating the efficiency of an electrical engine. While trying to get a better understanding of the results, I was wondering if the input value (y) used for updating the table data is interpolated between the corresponding break points.

While I was looking through the code files (lookup_methods.c, lookup_methods.h and sfun_lookupnd_stair_fit.c), I could find a calculation of a fraction variable that looks like it will be used for interpolating the input value according to the breakpoints, but i couldn't find that this information is used in any other place.

So my question is: is there any use of interpolation in the adaptive lookup table or not?

Best regards

Daniel

Answer 1

Adaptive lookup tables do not use interpolation between breakpoints to compute new table cell values or the output because each table cell (rectangle, hypercube) is represented by a single value. In 2D, this is equivalent to having a horizontal rectangle to represent the height of the table cell. Once the cell for a given input signal is found, the input value is used to update the "height" of the cell.

The picture on the Adaptive Lookup Table (1D Stair-Fit) block represents this case.