fix IndexError in internal_minima
fix IndexError in internal_minima

Variable i was not initialized prior to its use in line 26.
daler/MACS,daler/MACS,vd4mmind/MACS,daler/MACS,taoliu/MACS,taoliu/MACS,vd4mmind/MACS,taoliu/MACS,vd4mmind/MACS