[Jprogramming] inverse permutation vector

[bill lam]

Hello, I want to find the inverse permutation vector, eg
    ]pv=. /:a=. 10 13 14 10 15 12
0 3 5 1 2 4
    pv{a
10 10 12 13 14 15

how to get ipv from pv such that
    ipv{pv{a   give back   a

TIA

-- 
regards,
bill