diff options
Diffstat (limited to 'python/pyspark')
| -rw-r--r-- | python/pyspark/accumulators.py | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/python/pyspark/accumulators.py b/python/pyspark/accumulators.py index 438af4cfc0..c00c3a37af 100644 --- a/python/pyspark/accumulators.py +++ b/python/pyspark/accumulators.py @@ -76,6 +76,18 @@ def _deserialize_accumulator(aid, zero_value, accum_param): class Accumulator(object): + """ + A shared variable that can be accumulated, i.e., has a commutative and associative "add" + operation. Worker tasks on a Spark cluster can add values to an Accumulator with the C{+=} + operator, but only the driver program is allowed to access its value, using C{value}. + Updates from the workers get propagated automatically to the driver program. + + While C{SparkContext} supports accumulators for primitive data types like C{int} and + C{float}, users can also define accumulators for custom types by providing a custom + C{AccumulatorParam} object with a C{zero} and C{addInPlace} method. Refer to the doctest + of this module for an example. + """ + def __init__(self, aid, value, accum_param): """Create a new Accumulator with a given initial value and AccumulatorParam object""" from pyspark.accumulators import _accumulatorRegistry |