This field comparator is for numeric fields, where a given maximal
absolute difference can be tolerated. This difference has to be set by
the argument `max_abs_diff`

as a positive value. The default
value is , i.e. no difference is tolerated.

The agreement weight is returned if the numbers are the same, and the
disagreement weight if the absolute difference is larger than the
`max_abs_diff`

value. If the absolute difference between the
two values is larger than but equal to or smaller than
`max_abs_diff`

the partial agreement weight is calculated
according to the following formula.

where the absolute difference between the two values is calculated as

In its current version no frequency dependent weight calculation is
possible, thus the arguments `frequency_table`

,
`freq_table_max_weight`

and `freq_table_min_weight`

can not be used with this field comparator function.