setDefaultDistance: Set the default distance function for a descriptor type
Description
Set the default distance function for a descriptor type. This is the distance function
that will be used if none is given for a particular function call.
Usage
setDefaultDistance(descriptorType, distance)
Arguments
descriptorType
The type of the descriptor to set a distance function for. Built-in values
are "ap" and "fp". Additional values can be set as well.
distance
A distance function taking two descriptor objects (as returned by toObject in a descriptor transform,
see ink{addTransform} for details), and returning a distance value.