[jira] [Closed] (SINGA-478) Python 3 uses __itruediv__ instead of __idiv__

["YEUNG SAI HO (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SINGA-478?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

YEUNG SAI HO closed SINGA-478.
------------------------------

resolved

> Python 3 uses __itruediv__ instead of __idiv__
> ----------------------------------------------
>
>                 Key: SINGA-478
>                 URL: https://issues.apache.org/jira/browse/SINGA-478
>             Project: Singa
>          Issue Type: Improvement
>          Components: Core
>            Reporter: YEUNG SAI HO
>            Priority: Major
>          Time Spent: 1h 40m
>  Remaining Estimate: 0h
>
> We need to add  __itruediv__ in tensor.py because the original __idiv__ is not supported by python 3 anymore.
>  
> To understand the problem, let's study the following code first:
> {code:java}
> from singa import tensor
> from singa import device
> import numpy as np
> Y = np.ones(shape=[10],dtype=np.float32) * 10.0
> y = tensor.from_numpy(Y)
> y.to_device(device.get_default_device())
> def divide(y):
>    y /= 10
> divide(y)
> print(tensor.to_numpy(y))
> {code}
>  Without adding the {color:#333333}__itruediv__{color} function, the result is as follows, which means that the /= operation is not in place: 
> {code:java}
> [10. 10. 10. 10. 10. 10. 10. 10. 10. 10.]
> {code}
> After adding the __itruediv__ function, the result is as follows, which means that the /= operation is in place:
> {code:java}
> [1. 1. 1. 1. 1. 1. 1. 1. 1. 1.]
> {code}
> This is because the {color:#333333}__idiv__ operation is for python 2, while __itruediv__ is for python 3. Therefore, if we do not add the __itruediv__ operator in tensor.py, it just uses a default operation which is not in place.{color}
>  
>  



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