65083e93dd
This PR check all of the existing Python MLlib API to make sure that numpy.array is supported as Vector (also RDD of numpy.array). It also improve some docstring and doctest. cc mateiz mengxr Author: Davies Liu <davies@databricks.com> Closes #3189 from davies/numpy and squashes the following commits: d5057c4 [Davies Liu] fix tests 6987611 [Davies Liu] support numpy.array for all MLlib API
186 lines
7.4 KiB
Python
186 lines
7.4 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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import numpy as np
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import warnings
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from pyspark.mllib.common import callMLlibFunc
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from pyspark.mllib.linalg import Vectors, SparseVector, _convert_to_vector
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from pyspark.mllib.regression import LabeledPoint
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class MLUtils(object):
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"""
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Helper methods to load, save and pre-process data used in MLlib.
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"""
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@staticmethod
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def _parse_libsvm_line(line, multiclass=None):
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"""
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Parses a line in LIBSVM format into (label, indices, values).
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"""
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if multiclass is not None:
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warnings.warn("deprecated", DeprecationWarning)
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items = line.split(None)
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label = float(items[0])
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nnz = len(items) - 1
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indices = np.zeros(nnz, dtype=np.int32)
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values = np.zeros(nnz)
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for i in xrange(nnz):
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index, value = items[1 + i].split(":")
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indices[i] = int(index) - 1
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values[i] = float(value)
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return label, indices, values
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@staticmethod
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def _convert_labeled_point_to_libsvm(p):
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"""Converts a LabeledPoint to a string in LIBSVM format."""
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assert isinstance(p, LabeledPoint)
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items = [str(p.label)]
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v = _convert_to_vector(p.features)
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if isinstance(v, SparseVector):
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nnz = len(v.indices)
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for i in xrange(nnz):
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items.append(str(v.indices[i] + 1) + ":" + str(v.values[i]))
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else:
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for i in xrange(len(v)):
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items.append(str(i + 1) + ":" + str(v[i]))
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return " ".join(items)
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@staticmethod
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def loadLibSVMFile(sc, path, numFeatures=-1, minPartitions=None, multiclass=None):
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"""
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Loads labeled data in the LIBSVM format into an RDD of
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LabeledPoint. The LIBSVM format is a text-based format used by
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LIBSVM and LIBLINEAR. Each line represents a labeled sparse
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feature vector using the following format:
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label index1:value1 index2:value2 ...
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where the indices are one-based and in ascending order. This
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method parses each line into a LabeledPoint, where the feature
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indices are converted to zero-based.
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:param sc: Spark context
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:param path: file or directory path in any Hadoop-supported file
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system URI
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:param numFeatures: number of features, which will be determined
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from the input data if a nonpositive value
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is given. This is useful when the dataset is
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already split into multiple files and you
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want to load them separately, because some
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features may not present in certain files,
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which leads to inconsistent feature
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dimensions.
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:param minPartitions: min number of partitions
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@return: labeled data stored as an RDD of LabeledPoint
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>>> from tempfile import NamedTemporaryFile
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>>> from pyspark.mllib.util import MLUtils
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>>> tempFile = NamedTemporaryFile(delete=True)
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>>> tempFile.write("+1 1:1.0 3:2.0 5:3.0\\n-1\\n-1 2:4.0 4:5.0 6:6.0")
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>>> tempFile.flush()
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>>> examples = MLUtils.loadLibSVMFile(sc, tempFile.name).collect()
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>>> tempFile.close()
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>>> type(examples[0]) == LabeledPoint
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True
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>>> print examples[0]
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(1.0,(6,[0,2,4],[1.0,2.0,3.0]))
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>>> type(examples[1]) == LabeledPoint
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True
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>>> print examples[1]
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(-1.0,(6,[],[]))
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>>> type(examples[2]) == LabeledPoint
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True
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>>> print examples[2]
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(-1.0,(6,[1,3,5],[4.0,5.0,6.0]))
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"""
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if multiclass is not None:
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warnings.warn("deprecated", DeprecationWarning)
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lines = sc.textFile(path, minPartitions)
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parsed = lines.map(lambda l: MLUtils._parse_libsvm_line(l))
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if numFeatures <= 0:
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parsed.cache()
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numFeatures = parsed.map(lambda x: -1 if x[1].size == 0 else x[1][-1]).reduce(max) + 1
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return parsed.map(lambda x: LabeledPoint(x[0], Vectors.sparse(numFeatures, x[1], x[2])))
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@staticmethod
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def saveAsLibSVMFile(data, dir):
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"""
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Save labeled data in LIBSVM format.
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:param data: an RDD of LabeledPoint to be saved
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:param dir: directory to save the data
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>>> from tempfile import NamedTemporaryFile
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>>> from fileinput import input
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>>> from glob import glob
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>>> from pyspark.mllib.util import MLUtils
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>>> examples = [LabeledPoint(1.1, Vectors.sparse(3, [(0, 1.23), (2, 4.56)])), \
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LabeledPoint(0.0, Vectors.dense([1.01, 2.02, 3.03]))]
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>>> tempFile = NamedTemporaryFile(delete=True)
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>>> tempFile.close()
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>>> MLUtils.saveAsLibSVMFile(sc.parallelize(examples), tempFile.name)
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>>> ''.join(sorted(input(glob(tempFile.name + "/part-0000*"))))
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'0.0 1:1.01 2:2.02 3:3.03\\n1.1 1:1.23 3:4.56\\n'
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"""
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lines = data.map(lambda p: MLUtils._convert_labeled_point_to_libsvm(p))
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lines.saveAsTextFile(dir)
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@staticmethod
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def loadLabeledPoints(sc, path, minPartitions=None):
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"""
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Load labeled points saved using RDD.saveAsTextFile.
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:param sc: Spark context
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:param path: file or directory path in any Hadoop-supported file
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system URI
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:param minPartitions: min number of partitions
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@return: labeled data stored as an RDD of LabeledPoint
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>>> from tempfile import NamedTemporaryFile
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>>> from pyspark.mllib.util import MLUtils
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>>> examples = [LabeledPoint(1.1, Vectors.sparse(3, [(0, -1.23), (2, 4.56e-7)])), \
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LabeledPoint(0.0, Vectors.dense([1.01, 2.02, 3.03]))]
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>>> tempFile = NamedTemporaryFile(delete=True)
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>>> tempFile.close()
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>>> sc.parallelize(examples, 1).saveAsTextFile(tempFile.name)
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>>> MLUtils.loadLabeledPoints(sc, tempFile.name).collect()
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[LabeledPoint(1.1, (3,[0,2],[-1.23,4.56e-07])), LabeledPoint(0.0, [1.01,2.02,3.03])]
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"""
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minPartitions = minPartitions or min(sc.defaultParallelism, 2)
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return callMLlibFunc("loadLabeledPoints", sc, path, minPartitions)
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def _test():
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import doctest
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from pyspark.context import SparkContext
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globs = globals().copy()
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# The small batch size here ensures that we see multiple batches,
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# even in these small test examples:
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globs['sc'] = SparkContext('local[2]', 'PythonTest', batchSize=2)
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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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