question: public static DBIDs randomSample ( DBIDs ids , double rate , Random random ) { if ( rate <= 0 ) { return ids ; } if ( rate < 1.1 ) { int size = Math . min ( ( int ) ( rate * ids . size ( ) ) , ids . size ( ) ) ; return randomSample ( ids , size , random ) ; } int size = Math . min ( ( int ) rate , ids . size ( ) ) ; return randomSample ( ids , size , random ) ; }
target:  Produce a random sample of the given DBIDs.