  We investigate the entangling capacity of dynamical operations when provided
with local ancilla. A comparison is made between the entangling capacity with
and without the assistance of prior entanglement. An analytic solution is found
for the log-negativity entangling capacity of two-qubit gates, which equals the
entanglement of the Choi matrix isomorphic to the unitary operator.
Surprisingly, the availability of prior entanglement does not affect this
result; a property we call resource independence of the entangling capacity. We
prove several useful upper-bounds on the entangling capacity that hold for
general qudit dynamical operations, and for a whole family of entanglement
monotones including log-negativity and log-robustness. The log-robustness
entangling capacity is shown to be resource independent for general dynamics.
We provide numerical results supporting a conjecture that the log-negativity
entangling capacity is resource independence for all two-qudit unitaries.
