aboutsummaryrefslogtreecommitdiff
path: root/examples/src/main/python/mllib/logistic_regression.py
blob: 8cae27fc4a52d2d843c389489253847896049c64 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
#
# 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.
#

"""
Logistic regression using MLlib.

This example requires NumPy (http://www.numpy.org/).
"""

from math import exp
import sys

import numpy as np
from pyspark import SparkContext
from pyspark.mllib.regression import LabeledPoint
from pyspark.mllib.classification import LogisticRegressionWithSGD


def parsePoint(line):
    """
    Parse a line of text into an MLlib LabeledPoint object.
    """
    values = [float(s) for s in line.split(' ')]
    if values[0] == -1:   # Convert -1 labels to 0 for MLlib
        values[0] = 0
    return LabeledPoint(values[0], values[1:])


if __name__ == "__main__":
    if len(sys.argv) != 3:
        print >> sys.stderr, "Usage: logistic_regression <file> <iterations>"
        exit(-1)
    sc = SparkContext(appName="PythonLR")
    points = sc.textFile(sys.argv[1]).map(parsePoint)
    iterations = int(sys.argv[2])
    model = LogisticRegressionWithSGD.train(points, iterations)
    print "Final weights: " + str(model.weights)
    print "Final intercept: " + str(model.intercept)
    sc.stop()