Improved look-up table query scaling with variable count

[EvertBunschoten]

Proposed Changes

The CLookUpTable class allows for the fast interpolation of unstructured 2D data.

It was found that the query time of this class scaled significantly with the number of output variables, indicating inefficiencies in the query process.

These inefficiencies came from string comparison routines in the GetIndexOfVar function of the CLookUpTable class. By implementing overloaded instances of the look-up functions which retrieve data from data indices directly, the query time efficiency scaling was significantly improved.

Also reduced duplicate code within the CLookUpTable class.

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[pcarruscag]

You may want to remove the string based interface since it's known to be inneficient.

[EvertBunschoten]

You may want to remove the string based interface since it's known to be inneficient.

When replacing the string-based with index-based look-up methods, the performance improves substantially. The figure below shows the average measured evaluation time (measured with chrono library) vs the number of output variables. It's clear that using index-based look-up methods results in reduced query time, as well as improved scaling.

[bigfooted]

Thanks Evert, it looks good to me, Also nice improvement in speed.