used by EditDistance: the cost of having to substitute one character for another
for the sub value to ever be used, it should be smaller than the COST_REMOVE_CHAR or COST_INSERT_CHAR values
(integer greater than 0)
used by EditDistance: the cost of having to swap two adjoinging characters
for the swap value to ever be used, it should be smaller than the COST_REMOVE_CHAR or COST_INSERT_CHAR values
(integer greater than 0)