Where do you find professor oak in Eterna City in Pokemon platinum?

when you get anational dex go to pal park he will give you a new app ten go to eterna city and go to his house <-------------this works

(when you talk to him he also gives you the up-grade. He says the up-grade evolves a Pokemon when it is traded while holding it the Pokemon is porygon) (you get porygon from a person in veilstone city)

go south of enterna city left of the eterna gym. There is a small house and there he is