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Diffstat (limited to 'doc/source/reference/c-api.ufunc.rst')
| -rw-r--r-- | doc/source/reference/c-api.ufunc.rst | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/doc/source/reference/c-api.ufunc.rst b/doc/source/reference/c-api.ufunc.rst index 79ad256f5..02a35cf56 100644 --- a/doc/source/reference/c-api.ufunc.rst +++ b/doc/source/reference/c-api.ufunc.rst @@ -93,12 +93,23 @@ Functions the corresponding 1-d loop function in the func array. :param types: - Must be of length (*nin* + *nout*) \* *ntypes*, and it - contains the data-types (built-in only) that the corresponding - function in the *func* array can deal with. + Length ``(nin + nout) * ntypes`` array of ``char`` encoding the + :ref:`PyArray_Descr.type_num` (built-in only) that the corresponding + function in the ``func`` array accepts. For instance, for a comparison + ufunc with three ``ntypes``, two ``nin`` and one ``nout``, where the + first function accepts :ref:`npy_int32` and the the second + :ref:`npy_int64`, with both returning :ref:`npy_bool`, ``types`` would + be ``(char[]) {5, 5, 0, 7, 7, 0}`` since ``NPY_INT32`` is 5, + ``NPY_INT64`` is 7, and ``NPY_BOOL`` is 0 (on the python side, these + are exposed via :ref:`dtype.num`, i.e., for the example here, + ``dtype(np.int32).num``, ``dtype(np.int64).num``, and + ``dtype(np.bool_).num``, resp.). + + :ref:`casting-rules` will be used at runtime to find the first + ``func`` callable by the input/output provided. :param ntypes: - How many different data-type "signatures" the ufunc has implemented. + How many different data-type-specific functions the ufunc has implemented. :param nin: The number of inputs to this operation. @@ -129,10 +140,11 @@ Functions int nin, int nout, int identity, char* name, char* doc, int unused, char *signature) This function is very similar to PyUFunc_FromFuncAndData above, but has - an extra *signature* argument, to define generalized universal functions. + an extra *signature* argument, to define a + :ref:`generalized universal functions <c-api.generalized-ufuncs>`. Similarly to how ufuncs are built around an element-by-element operation, - gufuncs are around subarray-by-subarray operations, the signature defining - the subarrays to operate on. + gufuncs are around subarray-by-subarray operations, the + :ref:`signature <details-of-signature>` defining the subarrays to operate on. :param signature: The signature for the new gufunc. Setting it to NULL is equivalent |