gridsearchtvsplit
功能介绍
gridsearch是通过参数数组组成的网格,对其中的每一组输入参数的组很分别进行训练,预测,评估。取得评估参数最优的模型,作为最终的返回模型
tv为训练验证,将数据按照比例切分为两份,对其中一份数据做训练,对剩余一份数据做预测和评估,得到一个评估结果。
此函数用tv方法得到每一个grid对应参数的评估结果,得到最优模型
参数说明
名称 | 中文名称 | 描述 | 类型 | 是否必须? | 默认值 |
---|---|---|---|---|---|
trainRatio | 训练集比例 | 训练集与验证集的划分比例,取值范围为(0, 1]。 | Double | 0.8 | |
ParamGrid | 参数网格 | 指定参数的网格 | ParamGrid | ✓ | —- |
Estimator | Estimator | 用于调优的Estimator | Estimator | ✓ | —- |
TuningEvaluator | 评估指标 | 用于选择最优模型的评估指标 | TuningEvaluator | ✓ | —- |
脚本示例
脚本代码
def adult(url):
data = (
CsvSourceBatchOp()
.setFilePath('http://alink-dataset.cn-hangzhou.oss.aliyun-inc.com/csv/adult_train.csv')
.setSchemaStr(
'age bigint, workclass string, fnlwgt bigint,'
'education string, education_num bigint,'
'marital_status string, occupation string,'
'relationship string, race string, sex string,'
'capital_gain bigint, capital_loss bigint,'
'hours_per_week bigint, native_country string,'
'label string'
)
)
return data
def adult_train():
return adult('http://alink-dataset.cn-hangzhou.oss.aliyun-inc.com/csv/adult_train.csv')
def adult_test():
return adult('http://alink-dataset.cn-hangzhou.oss.aliyun-inc.com/csv/adult_test.csv')
def adult_numerical_feature_strs():
return [
"age", "fnlwgt", "education_num",
"capital_gain", "capital_loss", "hours_per_week"
]
def adult_categorical_feature_strs():
return [
"workclass", "education", "marital_status",
"occupation", "relationship", "race", "sex",
"native_country"
]
def adult_features_strs():
feature = adult_numerical_feature_strs()
feature.extend(adult_categorical_feature_strs())
return feature
def rf_grid_search_cv(featureCols, categoryFeatureCols, label, metric):
rf = (
RandomForestClassifier()
.setFeatureCols(featureCols)
.setCategoricalCols(categoryFeatureCols)
.setLabelCol(label)
.setPredictionCol('prediction')
.setPredictionDetailCol('prediction_detail')
)
paramGrid = (
ParamGrid()
.addGrid(rf, 'SUBSAMPLING_RATIO', [1.0, 0.99, 0.98])
.addGrid(rf, 'NUM_TREES', [3, 6, 9])
)
tuningEvaluator = (
BinaryClassificationTuningEvaluator()
.setLabelCol(label)
.setPredictionDetailCol("prediction_detail")
.setMetricName(metric)
)
cv = (
GridSearchCV()
.setEstimator(rf)
.setParamGrid(paramGrid)
.setTuningEvaluator(tuningEvaluator)
.setNumFolds(2)
)
return cv
def rf_grid_search_tv(featureCols, categoryFeatureCols, label, metric):
rf = (
RandomForestClassifier()
.setFeatureCols(featureCols)
.setCategoricalCols(categoryFeatureCols)
.setLabelCol(label)
.setPredictionCol('prediction')
.setPredictionDetailCol('prediction_detail')
)
paramGrid = (
ParamGrid()
.addGrid(rf, 'SUBSAMPLING_RATIO', [1.0, 0.99, 0.98])
.addGrid(rf, 'NUM_TREES', [3, 6, 9])
)
tuningEvaluator = (
BinaryClassificationTuningEvaluator()
.setLabelCol(label)
.setPredictionDetailCol("prediction_detail")
.setMetricName(metric)
)
cv = (
GridSearchTVSplit()
.setEstimator(rf)
.setParamGrid(paramGrid)
.setTuningEvaluator(tuningEvaluator)
)
return cv
def tuningcv(cv_estimator, input):
return cv_estimator.fit(input)
def tuningtv(tv_estimator, input):
return tv_estimator.fit(input)
def main():
print('rf cv tuning')
model = tuningcv(
rf_grid_search_cv(adult_features_strs(),
adult_categorical_feature_strs(), 'label', 'AUC'),
adult_train()
)
print(model.getReport())
print('rf tv tuning')
model = tuningtv(
rf_grid_search_tv(adult_features_strs(),
adult_categorical_feature_strs(), 'label', 'AUC'),
adult_train()
)
print(model.getReport())
main()
脚本结果
rf cv tuning
com.alibaba.alink.pipeline.tuning.GridSearchCV
[ {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 3
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 1.0
} ],
"metric" : 0.8922549257899725
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 3
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.99
} ],
"metric" : 0.8920255970548456
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 3
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.98
} ],
"metric" : 0.8944982480437225
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 6
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 1.0
} ],
"metric" : 0.8923867598288401
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 6
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.99
} ],
"metric" : 0.9012141767959505
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 6
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.98
} ],
"metric" : 0.8993774036693788
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 9
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 1.0
} ],
"metric" : 0.8981738808130779
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 9
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.99
} ],
"metric" : 0.9029671873892725
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 9
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.98
} ],
"metric" : 0.905228896323363
} ]
rf tv tuning
com.alibaba.alink.pipeline.tuning.GridSearchTVSplit
[ {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 3
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 1.0
} ],
"metric" : 0.9022694229691741
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 3
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.99
} ],
"metric" : 0.8963559966080328
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 3
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.98
} ],
"metric" : 0.9041948454957178
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 6
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 1.0
} ],
"metric" : 0.8982021117392784
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 6
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.99
} ],
"metric" : 0.9031851535310546
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 6
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.98
} ],
"metric" : 0.9034443322241488
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 9
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 1.0
} ],
"metric" : 0.8993474753000145
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 9
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.99
} ],
"metric" : 0.9090250137144916
}, {
"param" : [ {
"stage" : "RandomForestClassifier",
"paramName" : "numTrees",
"paramValue" : 9
}, {
"stage" : "RandomForestClassifier",
"paramName" : "subsamplingRatio",
"paramValue" : 0.98
} ],
"metric" : 0.9129786771786127
} ]