  We compute entanglement cost and distillable entanglement of states supported
on symmetric subspace. Not only giving general formula, we apply them to the
output states of optimal cloning machines. Surprisingly, under some settings,
the optimal n to m clone and true m copies are the same in entanglement
measures. However, they differ in the error exponent of entanglement dilution.
We also presented a general theory of entanglement dilution which is applicable
to any non-i.i.d sequence of states.
