Auto negotiation

Hi guys,

I understand on Cisco switches you disable auto negotiation by setting the speed and duplex. i.e.

interface gigabitethernet0/1

 speed 100

 duplex full

My question is: do you have to set BOTH to disable auto negotiation? For example if you just set speed 100, will the switch still negotiate the duplex? Or what about if I fix the duplex only, will it negotiate the speed?

Thanks.