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| author | Darren Dale <dsdale24@gmail.com> | 2009-08-23 16:30:28 +0000 |
|---|---|---|
| committer | Darren Dale <dsdale24@gmail.com> | 2009-08-23 16:30:28 +0000 |
| commit | 9e053da77d773fb22ee83219ad5595af6c73c953 (patch) | |
| tree | 955f7f9eae0d972c8d12019b5b873811de136505 /doc/source/reference/ufuncs.rst | |
| parent | 856a9363bf28da036c6102fc77ea7fcdba5e777a (diff) | |
| download | numpy-9e053da77d773fb22ee83219ad5595af6c73c953.tar.gz | |
add support for __array_prepare__
Diffstat (limited to 'doc/source/reference/ufuncs.rst')
| -rw-r--r-- | doc/source/reference/ufuncs.rst | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/doc/source/reference/ufuncs.rst b/doc/source/reference/ufuncs.rst index 09b13dc89..8096e1497 100644 --- a/doc/source/reference/ufuncs.rst +++ b/doc/source/reference/ufuncs.rst @@ -102,19 +102,24 @@ Output type determination The output of the ufunc (and its methods) is not necessarily an :class:`ndarray`, if all input arguments are not :class:`ndarrays <ndarray>`. -All output arrays will be passed to the :obj:`__array_wrap__` -method of the input (besides :class:`ndarrays <ndarray>`, and scalars) -that defines it **and** has the highest :obj:`__array_priority__` of -any other input to the universal function. The default -:obj:`__array_priority__` of the ndarray is 0.0, and the default -:obj:`__array_priority__` of a subtype is 1.0. Matrices have -:obj:`__array_priority__` equal to 10.0. +All output arrays will be passed to the :obj:`__array_prepare__` and +:obj:`__array_wrap__` methods of the input (besides +:class:`ndarrays <ndarray>`, and scalars) that defines it **and** has +the highest :obj:`__array_priority__` of any other input to the +universal function. The default :obj:`__array_priority__` of the +ndarray is 0.0, and the default :obj:`__array_priority__` of a subtype +is 1.0. Matrices have :obj:`__array_priority__` equal to 10.0. The ufuncs can also all take output arguments. The output will be cast if necessary to the provided output array. If a class with an :obj:`__array__` method is used for the output, results will be written to the object returned by :obj:`__array__`. Then, if the class -also has an :obj:`__array_wrap__` method, the returned +also has an :obj:`__array_prepare__` method, it is called so metadata +may be determined based on the context of the ufunc (the context +consisting of the ufunc itself, the arguments passed to the ufunc, and +the ufunc domain.) The array object returned by +:obj:`__array_prepare__` is passed to the ufunc for computation. +Finally, if the class also has an :obj:`__array_wrap__` method, the returned :class:`ndarray` result will be passed to that method just before passing control back to the caller. |