Ticket #3856 (closed defect: invalid)

Opened 4 months ago

Last modified 3 months ago

Multiply between QQ and GF(7) gives exception

Reported by: gfurnish Assigned to: robertwb
Priority: major Milestone: sage-duplicate/invalid/wontfix
Component: coercion Keywords:
Cc:

Description 

sage: 1/4*GF(7)['t'](1)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

/home/gfurnish/coercion-test/sage-3.1.alpha2-sage.math-only-x86_64-Linux/<ipython console> in <module>()

/home/gfurnish/coercion-test/sage-3.1.alpha2-sage.math-only-x86_64-Linux/element.pyx in sage.structure.element.RingElement.__mul__ (sage/structure/element.c:9190)()

/home/gfurnish/coercion-test/sage-3.1.alpha2-sage.math-only-x86_64-Linux/coerce.pyx in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:6288)()

TypeError: unsupported operand parent(s) for '*': 'Rational Field' and 'Univariate Polynomial Ring in t over Finite Field of size 7'

This is implied to work by the following doctest in coercion_maps.pyx 

            sage: mor = NamedConvertMap(SR, GF(7)[['t']], '_polynomial_')
            sage: mor(x^2/4+1)
            1 + 2*t^2

Change History

(follow-up: ↓ 3 ) 08/14/2008 02:31:51 PM changed by robertwb

I don't think this is a bug, this should *not* work. Conversion != Coercion.

08/15/2008 12:31:25 PM changed by gfurnish

So _polynomial_ should also create any underlying conversions needed?

(in reply to: ↑ 1 ) 08/26/2008 02:58:32 AM changed by mabshoff

  • status changed from new to closed.
  • resolution set to invalid.
  • milestone changed from sage-3.1.2 to sage-duplicate/invalid.

Replying to robertwb:

I don't think this is a bug, this should *not* work. Conversion != Coercion.

Hence this is invalid.

Cheers,

Michael