x and y can be
distances (InfinitySparseMatrix, BlockedInfinitySparseMatrix,
or DenseMatrix), or they can be optmatch objects.To save space, optmatch objects merely store a hash of the distance
matrix instead of the original object. Any distance objects are hashed before
comparison.
optmatch_same_distance(x, y)A distances (InfinitySparseMatrix,
BlockedInfinitySparseMatrix, or DenseMatrix), or
optmatch object.
A distances (InfinitySparseMatrix,
BlockedInfinitySparseMatrix, or DenseMatrix), or
optmatch object.
Boolean whether the two distance specifications are identical.
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 but
have differeing calls.)