研究lightgbm超参数及增量学习

    "lightgbm": {
      "n_estimators": 2000,
      "boosting_type":  "gbdt",
      "num_leaves":  {"_type": "int_quniform", "_value": [10,150],"_default": 31},
      "max_depth": {"_type": "int_quniform", "_value": [1,100],"_default": 31},
      "learning_rate": {"_type": "loguniform", "_value": [1e-2,0.2],"_default": 0.1},
      "subsample_for_bin": {"_type": "int_quniform","_value": [2e4, 3e5, 2e4],"_default": 20000},
      "feature_fraction": {"_type": "quniform","_value": [0.5,1,0.05],"_default": 1},
      "bagging_fraction": {"_type