Error in LookUpTableModule

Error relates to rounding of position to indices.

r_as_bin_indices is achieved as follows current:

r_as_bin_indices = (r - r_min) / r_extent * n_bins where r_extent = r_max - r_min and n_bins is the size of the lookup map

Examples

Consider the case where the map is [1 1.5 2 2.5 3 3.5]. In this case, r_extent = 2.5 and n_bins = 6.

Now if we were to look for the closest bin to r = 1.24 we would expect r_as_bin_indices = 0 after rounding.

However what we actually get is (1.24 - 1)/2.5 * 6 = 0.576 which rounds up to 1

If instead we use floor instead of rounding, we get an issue in the case of r = 1.4, where we would expect bin 0 but get bin 1.

Fix

Replace n_bins from shape[] to shape[] - 1