def set_dim(self,numprom,numbiprom,numdown):
        
        self.numprom=numprom
        self.numbiprom=numbiprom
        self.numdown=numdown
Set the dimenstions of promoter, bipromoter and downstream
dataset/ETHPy150Open taoliu/taolib/Assoc/tables.py/PGBG.set_dim