ccafd757ed
This PR changes lambda scaling from number of users/items to number of explicit ratings. The latter is the behavior in 1.2. Slight refactor of NormalEquation to make it independent of ALS models. srowen codexiang Author: Xiangrui Meng <meng@databricks.com> Closes #5314 from mengxr/SPARK-6642 and squashes the following commits: dc655a1 [Xiangrui Meng] relax python tests f410df2 [Xiangrui Meng] use 1.2 scaling and remove addImplicit from NormalEquation
164 lines
5.4 KiB
Python
164 lines
5.4 KiB
Python
#
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# Licensed to the Apache Software Foundation (ASF) under one or more
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# contributor license agreements. See the NOTICE file distributed with
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# this work for additional information regarding copyright ownership.
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# The ASF licenses this file to You under the Apache License, Version 2.0
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# (the "License"); you may not use this file except in compliance with
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# the License. You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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from collections import namedtuple
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from pyspark import SparkContext
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from pyspark.rdd import RDD
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from pyspark.mllib.common import JavaModelWrapper, callMLlibFunc, inherit_doc
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from pyspark.mllib.util import JavaLoader, JavaSaveable
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__all__ = ['MatrixFactorizationModel', 'ALS', 'Rating']
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class Rating(namedtuple("Rating", ["user", "product", "rating"])):
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"""
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Represents a (user, product, rating) tuple.
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>>> r = Rating(1, 2, 5.0)
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>>> (r.user, r.product, r.rating)
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(1, 2, 5.0)
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>>> (r[0], r[1], r[2])
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(1, 2, 5.0)
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"""
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def __reduce__(self):
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return Rating, (int(self.user), int(self.product), float(self.rating))
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@inherit_doc
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class MatrixFactorizationModel(JavaModelWrapper, JavaSaveable, JavaLoader):
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"""A matrix factorisation model trained by regularized alternating
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least-squares.
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>>> r1 = (1, 1, 1.0)
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>>> r2 = (1, 2, 2.0)
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>>> r3 = (2, 1, 2.0)
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>>> ratings = sc.parallelize([r1, r2, r3])
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>>> model = ALS.trainImplicit(ratings, 1, seed=10)
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>>> model.predict(2, 2)
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0.4...
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>>> testset = sc.parallelize([(1, 2), (1, 1)])
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>>> model = ALS.train(ratings, 2, seed=0)
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>>> model.predictAll(testset).collect()
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[Rating(user=1, product=1, rating=1.0...), Rating(user=1, product=2, rating=1.9...)]
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>>> model = ALS.train(ratings, 4, seed=10)
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>>> model.userFeatures().collect()
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[(1, array('d', [...])), (2, array('d', [...]))]
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>>> first_user = model.userFeatures().take(1)[0]
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>>> latents = first_user[1]
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>>> len(latents) == 4
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True
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>>> model.productFeatures().collect()
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[(1, array('d', [...])), (2, array('d', [...]))]
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>>> first_product = model.productFeatures().take(1)[0]
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>>> latents = first_product[1]
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>>> len(latents) == 4
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True
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>>> model = ALS.train(ratings, 1, nonnegative=True, seed=10)
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>>> model.predict(2,2)
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3.8...
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>>> model = ALS.trainImplicit(ratings, 1, nonnegative=True, seed=10)
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>>> model.predict(2,2)
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0.4...
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>>> import os, tempfile
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>>> path = tempfile.mkdtemp()
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>>> model.save(sc, path)
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>>> sameModel = MatrixFactorizationModel.load(sc, path)
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>>> sameModel.predict(2,2)
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0.4...
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>>> sameModel.predictAll(testset).collect()
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[Rating(...
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>>> try:
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... os.removedirs(path)
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... except OSError:
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... pass
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"""
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def predict(self, user, product):
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return self._java_model.predict(int(user), int(product))
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def predictAll(self, user_product):
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assert isinstance(user_product, RDD), "user_product should be RDD of (user, product)"
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first = user_product.first()
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assert len(first) == 2, "user_product should be RDD of (user, product)"
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user_product = user_product.map(lambda (u, p): (int(u), int(p)))
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return self.call("predict", user_product)
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def userFeatures(self):
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return self.call("getUserFeatures")
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def productFeatures(self):
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return self.call("getProductFeatures")
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@classmethod
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def load(cls, sc, path):
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model = cls._load_java(sc, path)
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wrapper = sc._jvm.MatrixFactorizationModelWrapper(model)
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return MatrixFactorizationModel(wrapper)
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class ALS(object):
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@classmethod
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def _prepare(cls, ratings):
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assert isinstance(ratings, RDD), "ratings should be RDD"
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first = ratings.first()
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if not isinstance(first, Rating):
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if isinstance(first, (tuple, list)):
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ratings = ratings.map(lambda x: Rating(*x))
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else:
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raise ValueError("rating should be RDD of Rating or tuple/list")
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return ratings
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@classmethod
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def train(cls, ratings, rank, iterations=5, lambda_=0.01, blocks=-1, nonnegative=False,
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seed=None):
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model = callMLlibFunc("trainALSModel", cls._prepare(ratings), rank, iterations,
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lambda_, blocks, nonnegative, seed)
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return MatrixFactorizationModel(model)
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@classmethod
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def trainImplicit(cls, ratings, rank, iterations=5, lambda_=0.01, blocks=-1, alpha=0.01,
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nonnegative=False, seed=None):
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model = callMLlibFunc("trainImplicitALSModel", cls._prepare(ratings), rank,
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iterations, lambda_, blocks, alpha, nonnegative, seed)
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return MatrixFactorizationModel(model)
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def _test():
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import doctest
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import pyspark.mllib.recommendation
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globs = pyspark.mllib.recommendation.__dict__.copy()
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globs['sc'] = SparkContext('local[4]', 'PythonTest')
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(failure_count, test_count) = doctest.testmod(globs=globs, optionflags=doctest.ELLIPSIS)
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globs['sc'].stop()
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if failure_count:
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exit(-1)
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if __name__ == "__main__":
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_test()
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