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author | Xiangrui Meng <meng@databricks.com> | 2014-11-03 12:24:24 -0800 |
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committer | Xiangrui Meng <meng@databricks.com> | 2014-11-03 12:24:24 -0800 |
commit | 3cca1962207745814b9d83e791713c91b659c36c (patch) | |
tree | 997330407c25dabe70d5792421ce6e831976300b /python/pyspark/rdd.py | |
parent | 2aca97c7cfdefea8b6f9dbb88951e9acdfd606d9 (diff) | |
download | spark-3cca1962207745814b9d83e791713c91b659c36c.tar.gz spark-3cca1962207745814b9d83e791713c91b659c36c.tar.bz2 spark-3cca1962207745814b9d83e791713c91b659c36c.zip |
[SPARK-4148][PySpark] fix seed distribution and add some tests for rdd.sample
The current way of seed distribution makes the random sequences from partition i and i+1 offset by 1.
~~~
In [14]: import random
In [15]: r1 = random.Random(10)
In [16]: r1.randint(0, 1)
Out[16]: 1
In [17]: r1.random()
Out[17]: 0.4288890546751146
In [18]: r1.random()
Out[18]: 0.5780913011344704
In [19]: r2 = random.Random(10)
In [20]: r2.randint(0, 1)
Out[20]: 1
In [21]: r2.randint(0, 1)
Out[21]: 0
In [22]: r2.random()
Out[22]: 0.5780913011344704
~~~
Note: The new tests are not for this bug fix.
Author: Xiangrui Meng <meng@databricks.com>
Closes #3010 from mengxr/SPARK-4148 and squashes the following commits:
869ae4b [Xiangrui Meng] move tests tests.py
c1bacd9 [Xiangrui Meng] fix seed distribution and add some tests for rdd.sample
Diffstat (limited to 'python/pyspark/rdd.py')
-rw-r--r-- | python/pyspark/rdd.py | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/python/pyspark/rdd.py b/python/pyspark/rdd.py index 550c9dd805..4f025b9f11 100644 --- a/python/pyspark/rdd.py +++ b/python/pyspark/rdd.py @@ -316,9 +316,6 @@ class RDD(object): """ Return a sampled subset of this RDD (relies on numpy and falls back on default random generator if numpy is unavailable). - - >>> sc.parallelize(range(0, 100)).sample(False, 0.1, 2).collect() #doctest: +SKIP - [2, 3, 20, 21, 24, 41, 42, 66, 67, 89, 90, 98] """ assert fraction >= 0.0, "Negative fraction value: %s" % fraction return self.mapPartitionsWithIndex(RDDSampler(withReplacement, fraction, seed).func, True) |