optmatch_same_distance: Checks if the distance newdist is identical to the distance used to
generate the optmatch object obj.
Description
To save space, optmatch objects merely store a hash of
the distance matrix instead of the original object. This
checks if the hash of newdist is identical to the
hash currently saved in obj.Usage
optmatch_same_distance(obj, newdist)
Value
- Boolean whether the two distance specifications are
identical.
Details
Note that the distance is hashed with its call set
to NULL. (This avoids issues where, for example,
match_on(Z~X, data=d, caliper=NULL) and
match_on(Z~x, data=d) produce identical matches
(since the default argument to caliper is
NULL) but distinct calls.)