# # Licensed to the Apache Software Foundation (ASF) under one or more # contributor license agreements. See the NOTICE file distributed with # this work for additional information regarding copyright ownership. # The ASF licenses this file to You under the Apache License, Version 2.0 # (the "License"); you may not use this file except in compliance with # the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # import array import sys from collections import namedtuple from pyspark import SparkContext, since from pyspark.rdd import RDD from pyspark.mllib.common import JavaModelWrapper, callMLlibFunc, inherit_doc from pyspark.mllib.util import JavaLoader, JavaSaveable from pyspark.sql import DataFrame __all__ = ["MatrixFactorizationModel", "ALS", "Rating"] [docs]class Rating(namedtuple("Rating", ["user", "product", "rating"])): """ Represents a (user, product, rating) tuple. .. versionadded:: 1.2.0 Examples -------- >>> r = Rating(1, 2, 5.0) >>> (r.user, r.product, r.rating) (1, 2, 5.0) >>> (r[0], r[1], r[2]) (1, 2, 5.0) """ def __reduce__(self): return Rating, (int(self.user), int(self.product), float(self.rating)) [docs]@inherit_doc class MatrixFactorizationModel(JavaModelWrapper, JavaSaveable, JavaLoader): """A matrix factorisation model trained by regularized alternating least-squares. .. versionadded:: 0.9.0 Examples -------- >>> r1 = (1, 1, 1.0) >>> r2 = (1, 2, 2.0) >>> r3 = (2, 1, 2.0) >>> ratings = sc.parallelize([r1, r2, r3]) >>> model = ALS.trainImplicit(ratings, 1, seed=10) >>> model.predict(2, 2) 0.4... >>> testset = sc.parallelize([(1, 2), (1, 1)]) >>> model = ALS.train(ratings, 2, seed=0) >>> model.predictAll(testset).collect() [Rating(user=1, product=1, rating=1.0...), Rating(user=1, product=2, rating=1.9...)] >>> model = ALS.train(ratings, 4, seed=10) >>> model.userFeatures().collect() [(1, array('d', [...])), (2, array('d', [...]))] >>> model.recommendUsers(1, 2) [Rating(user=2, product=1, rating=1.9...), Rating(user=1, product=1, rating=1.0...)] >>> model.recommendProducts(1, 2) [Rating(user=1, product=2, rating=1.9...), Rating(user=1, product=1, rating=1.0...)] >>> model.rank 4 >>> first_user = model.userFeatures().take(1)[0] >>> latents = first_user[1] >>> len(latents) 4 >>> model.productFeatures().collect() [(1, array('d', [...])), (2, array('d', [...]))] >>> first_product = model.productFeatures().take(1)[0] >>> latents = first_product[1] >>> len(latents) 4 >>> products_for_users = model.recommendProductsForUsers(1).collect() >>> len(products_for_users) 2 >>> products_for_users[0] (1, (Rating(user=1, product=2, rating=...),)) >>> users_for_products = model.recommendUsersForProducts(1).collect() >>> len(users_for_products) 2 >>> users_for_products[0] (1, (Rating(user=2, product=1, rating=...),)) >>> model = ALS.train(ratings, 1, nonnegative=True, seed=123456789) >>> model.predict(2, 2) 3.73... >>> df = sqlContext.createDataFrame([Rating(1, 1, 1.0), Rating(1, 2, 2.0), Rating(2, 1, 2.0)]) >>> model = ALS.train(df, 1, nonnegative=True, seed=123456789) >>> model.predict(2, 2) 3.73... >>> model = ALS.trainImplicit(ratings, 1, nonnegative=True, seed=123456789) >>> model.predict(2, 2) 0.4... >>> import os, tempfile >>> path = tempfile.mkdtemp() >>> model.save(sc, path) >>> sameModel = MatrixFactorizationModel.load(sc, path) >>> sameModel.predict(2, 2) 0.4... >>> sameModel.predictAll(testset).collect() [Rating(... >>> from shutil import rmtree >>> try: ... rmtree(path) ... except OSError: ... pass """ [docs] @since("0.9.0") def predict(self, user, product): """ Predicts rating for the given user and product. """ return self._java_model.predict(int(user), int(product)) [docs] @since("0.9.0") def predictAll(self, user_product): """ Returns a list of predicted ratings for input user and product pairs. """ assert isinstance(user_product, RDD), "user_product should be RDD of (user, product)" first = user_product.first() assert len(first) == 2, "user_product should be RDD of (user, product)" user_product = user_product.map(lambda u_p: (int(u_p[0]), int(u_p[1]))) return self.call("predict", user_product) [docs] @since("1.2.0") def userFeatures(self): """ Returns a paired RDD, where the first element is the user and the second is an array of features corresponding to that user. """ return self.call("getUserFeatures").mapValues(lambda v: array.array("d", v)) [docs] @since("1.2.0") def productFeatures(self): """ Returns a paired RDD, where the first element is the product and the second is an array of features corresponding to that product. """ return self.call("getProductFeatures").mapValues(lambda v: array.array("d", v)) [docs] @since("1.4.0") def recommendUsers(self, product, num): """ Recommends the top "num" number of users for a given product and returns a list of Rating objects sorted by the predicted rating in descending order. """ return list(self.call("recommendUsers", product, num)) [docs] @since("1.4.0") def recommendProducts(self, user, num): """ Recommends the top "num" number of products for a given user and returns a list of Rating objects sorted by the predicted rating in descending order. """ return list(self.call("recommendProducts", user, num)) [docs] def recommendProductsForUsers(self, num): """ Recommends the top "num" number of products for all users. The number of recommendations returned per user may be less than "num". """ return self.call("wrappedRecommendProductsForUsers", num) [docs] def recommendUsersForProducts(self, num): """ Recommends the top "num" number of users for all products. The number of recommendations returned per product may be less than "num". """ return self.call("wrappedRecommendUsersForProducts", num) @property @since("1.4.0") def rank(self): """Rank for the features in this model""" return self.call("rank") [docs] @classmethod @since("1.3.1") def load(cls, sc, path): """Load a model from the given path""" model = cls._load_java(sc, path) wrapper = sc._jvm.org.apache.spark.mllib.api.python.MatrixFactorizationModelWrapper(model) return MatrixFactorizationModel(wrapper) [docs]class ALS: """Alternating Least Squares matrix factorization .. versionadded:: 0.9.0 """ @classmethod def _prepare(cls, ratings): if isinstance(ratings, RDD): pass elif isinstance(ratings, DataFrame): ratings = ratings.rdd else: raise TypeError( "Ratings should be represented by either an RDD or a DataFrame, " "but got %s." % type(ratings) ) first = ratings.first() if isinstance(first, Rating): pass elif isinstance(first, (tuple, list)): ratings = ratings.map(lambda x: Rating(*x)) else: raise TypeError("Expect a Rating or a tuple/list, but got %s." % type(first)) return ratings [docs] @classmethod def train( cls, ratings, rank, iterations=5, lambda_=0.01, blocks=-1, nonnegative=False, seed=None ): """ Train a matrix factorization model given an RDD of ratings by users for a subset of products. The ratings matrix is approximated as the product of two lower-rank matrices of a given rank (number of features). To solve for these features, ALS is run iteratively with a configurable level of parallelism. .. versionadded:: 0.9.0 Parameters ---------- ratings : :py:class:`pyspark.RDD` RDD of `Rating` or (userID, productID, rating) tuple. rank : int Number of features to use (also referred to as the number of latent factors). iterations : int, optional Number of iterations of ALS. (default: 5) lambda\\_ : float, optional Regularization parameter. (default: 0.01) blocks : int, optional Number of blocks used to parallelize the computation. A value of -1 will use an auto-configured number of blocks. (default: -1) nonnegative : bool, optional A value of True will solve least-squares with nonnegativity constraints. (default: False) seed : bool, optional Random seed for initial matrix factorization model. A value of None will use system time as the seed. (default: None) """ model = callMLlibFunc( "trainALSModel", cls._prepare(ratings), rank, iterations, lambda_, blocks, nonnegative, seed, ) return MatrixFactorizationModel(model) [docs] @classmethod def trainImplicit( cls, ratings, rank, iterations=5, lambda_=0.01, blocks=-1, alpha=0.01, nonnegative=False, seed=None, ): """ Train a matrix factorization model given an RDD of 'implicit preferences' of users for a subset of products. The ratings matrix is approximated as the product of two lower-rank matrices of a given rank (number of features). To solve for these features, ALS is run iteratively with a configurable level of parallelism. .. versionadded:: 0.9.0 Parameters ---------- ratings : :py:class:`pyspark.RDD` RDD of `Rating` or (userID, productID, rating) tuple. rank : int Number of features to use (also referred to as the number of latent factors). iterations : int, optional Number of iterations of ALS. (default: 5) lambda\\_ : float, optional Regularization parameter. (default: 0.01) blocks : int, optional Number of blocks used to parallelize the computation. A value of -1 will use an auto-configured number of blocks. (default: -1) alpha : float, optional A constant used in computing confidence. (default: 0.01) nonnegative : bool, optional A value of True will solve least-squares with nonnegativity constraints. (default: False) seed : int, optional Random seed for initial matrix factorization model. A value of None will use system time as the seed. (default: None) """ model = callMLlibFunc( "trainImplicitALSModel", cls._prepare(ratings), rank, iterations, lambda_, blocks, alpha, nonnegative, seed, ) return MatrixFactorizationModel(model) def _test(): import doctest import pyspark.mllib.recommendation from pyspark.sql import SQLContext globs = pyspark.mllib.recommendation.__dict__.copy() sc = SparkContext("local[4]", "PythonTest") globs["sc"] = sc globs["sqlContext"] = SQLContext(sc) (failure_count, test_count) = doctest.testmod(globs=globs, optionflags=doctest.ELLIPSIS) globs["sc"].stop() if failure_count: sys.exit(-1) if __name__ == "__main__": _test()