Merge a new coordinate/usrIds with an old set. Also, return an inverse map from the new usrIds to the extended vector. Merging is performed purely on usrIds. Any node in the new set with the same usrIds in the old array is mapped to the old set.


newUsrIds (array)
An array of new user indices.
newCrd (array)
An array of new coordinates.
oldUsrIds (array)
An array of old user indices.
oldCrd (array)
An array of old coordinates.

Return Value

usrIds (array)
New user indices.
crd (array)
New coordinates.