This may be the problem. Simple diffs are pleasant. I'm guessing
this code doesn't get a lot of testing. Glad it's there, though!
Geoffrey
diff --git a/numpy/core/src/umath/ufunc_type_resolution.c
b/numpy/core/src/umath/ufunc_type_resolution.c
index 0d6cf19..a93eda1 100644
--- a/numpy/core/src/umath/ufunc_type_resolution.c
+++ b/numpy/core/src/umath/ufunc_type_resolution.c
@@ -1866,7 +1866,7 @@ linear_search_type_resolver(PyUFuncObject *self,
case -1:
return -1;
/* A loop was found */
- case 1:
+ case 0:
return 0;
}
}
On Sun, Dec 4, 2011 at 9:29 AM, Charles R Harris
<charlesr.har...@gmail.com> wrote:
>
>
> On Sat, Dec 3, 2011 at 8:14 PM, Geoffrey Irving <irv...@naml.us> wrote:
>>
>> Hello,
>>
>> I'm trying to add a fixed precision rational number dtype to numpy,
>> and am running into an issue trying to register ufunc loops. The code
>> in question looks like
>>
>> int npy_rational = PyArray_RegisterDataType(&rational_descr);
>> PyObject* equal = ... // extract equal object from the imported numpy
>> module
>> int types[3] = {npy_rational,npy_rational,NPY_BOOL};
>> if
>> (PyUFunc_RegisterLoopForType((PyUFuncObject*)ufunc,npy_rational,rational_ufunc_##name,_types,0)<0)
>> return 0;
>>
>> In Python 2.6.7 with the latest numpy from git, I get
>>
>> >>> from rational import *
>> >>> i = array([rational(5,3)])
>> >>> i
>> array([5/3], dtype=rational)
>> >>> equal(i,i)
>> Traceback (most recent call last):
>> File "<stdin>", line 1, in <module>
>> TypeError: ufunc 'equal' not supported for the input types, and
>> the inputs could not be safely coerced to any supported types
>> according to the casting rule ''safe''
>>
>> The same thing happens with (rational,rational)->rational ufuncs like
>> multiply.
>>
>> The full extension module code is here:
>>
>> https://github.com/girving/poker/blob/rational/rational.cpp
>>
>> I realize this isn't much information to go on, but let me know if
>> anything comes to mind in terms of possible reasons or further tests
>> to run. Unfortunately it looks like the ufunc ntypes and types
>> properties aren't updated based on user-defined loops, so I'm not yet
>> sure if the problem is in registry or resolution.
>>
>> It's also possible someone else hit this before:
>> http://projects.scipy.org/numpy/ticket/1913.
>>
>
> I haven't tried adding a new type and can't offer any suggestions. But there
> was a recent implementation of a quaternion type that might be worth looking
> at for comparison. You can find it here.
>
> Chuck
>
>
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