pow(int, int, fmpz) is always 1 #92

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1. oscarbenjamin commented on Oct 2, 2023

   

   oscarbenjamin

   on Oct 2, 2023

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   Looks like the code here should be checking the type of s:
   

   python-flint/src/flint/types/fmpz.pyx

   Lines 362 to 371 in 98c2883

   	def __pow__(s, t, m):
   	cdef fmpz_struct tval[1]
   	cdef fmpz_struct mval[1]
   	cdef int ttype = FMPZ_UNKNOWN
   	cdef int mtype = FMPZ_UNKNOWN
   	cdef int success
   	u = NotImplemented
   	ttype = fmpz_set_any_ref(tval, t)
   	if ttype == FMPZ_UNKNOWN:
   	return NotImplemented

   
   I hadn't contemplated that __pow__(s, t, m) might be called with s not being an fmpz. At this line s will be an int (PyLong):
   

   python-flint/src/flint/types/fmpz.pyx

   Line 405 in 98c2883

   fmpz_powm((<fmpz>u).val, (<fmpz>s).val, tval, mval)

   
   Presumably the bytes there look like a 1 as an fmpz_t.

   The fix is that the s argument should be handled in the same way as the t argument.
2. oscarbenjamin

   closed this as completedin #93on Oct 2, 2023
3. oscarbenjamin commented on Oct 2, 2023

   

   oscarbenjamin

   on Oct 2, 2023

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   Thanks for the bug report. This will be fixed in the next release.
4. haru-44 commented on Oct 2, 2023

   

   haru-44

   on Oct 2, 2023

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   Thanks for the correction.
5. jamestitus299

   added a commit that references this issue on Jul 4, 2024

   # int() can be removed when flintlib/python-flint#92

   3d94534