# Asym Rank by Date

### Description
Rank objects by the distance of a date property to a given value (or pair of values).
The assigned rank varies according to a bell-shaped curve centered at the given value.
Moreover, the ranking can be asymmetric meaning that one bell curve is used to the left of one value
and another bell curve to the right of the other value (the interval in between is ranked constantly 1).

### Input
- `SOURCE [OBJ]`: the list of objects to rank

### Output
- `CLOSE [OBJ]`: ranked objects, objects closed are ranked more highly
- `FAR [OBJ]`: ranked objects, objects further away are ranked more highly

### Parameters
- `Property`: the date property to check
- `Use sub-properties`: when set to `true`, the values of all sub properties are also included. Sub-properties
  can be defined in the data with the `rdfs:subPropertyOf` relation.
- `Ranking curve symmetry`: When `Symmetric`, a single ranking curve centered around `Value` is used.
  When `Asymmetric`, two ranking curves and values can be specified (see below).
- `Value`: the date against which the `Property` of each object is compared
- `Threshold distance`: The distance (in days) at which the specified `Rank at threshold distance` is attained.
  If set to 0, an indicator function is used as our ranking curve (i.e. all values not equal to `Value` are
  filtered out). If set to 1, a constant ranking curve with value 1 is used (i.e. ranks remain unchanged).
  These two options are really only useful in the asymmetric case.
- `Rank at threshold distance`: The rank to be attained at the specified `Threshold distance`. If set to 0,
  a bump function in the shape of the 5th order smoothstep function on both sides of `Value` is used as our
  ranking curve (see https://en.wikipedia.org/wiki/Smoothstep). If set to 1, a constant ranking curve with value
  1 is used (i.e. ranks remain unchanged). For all values in between, the ranking curve has the shape of a
  Gaussian centred at `Value` and with peak value 1.

When `Ranking curve symmetry` is `Asymmetric` then each of the curve parameters above can be
specified individually for the left and right side, respectively. The behaviour of each of
these is the same as for the symmetric case. The left-side ranking curve is applied to all
objects where the date of the selected `Property` lies in the past (to the left) of the specified `Left value`,
while the right-side ranking curve is applied to all objects where date of the the selected `Property` lies in
the future (to the right) of the specified `Right value`. Between these two values, a constant ranking curve
of value 1 is applied and so the rank is left unchanged.