tutorial tuning catboost
params = {'depth':[3,1,2,6,4,5,7,8,9,10],
'iterations':[250,100,500,1000],
'learning_rate':[0.03,0.001,0.01,0.1,0.2,0.3],
'l2_leaf_reg':[3,1,5,10,100],
'border_count':[32,5,10,20,50,100,200],
'ctr_border_count':[50,5,10,20,100,200],
'thread_count':4}