characteristic() should be an integer #12988

saraedum · 2012-05-21T16:47:11Z

Currently characteristic() does not return an Integer for some rings:

sage: type(ZZ.characteristic())
<type 'int'>

This is annoying because one cannot for example do:

sage: ZZ.characteristic().is_prime()
AttributeError: 'int' object has no attribute 'is_prime'

I don't see a good reason not to make characteristic always an Integer. The minimal performance loss should not be an issue in any computation that I can imagine.

Depends on #13043

Component: algebra

Keywords: ZZ characteristic sd40.5

Author: Julian Rueth

Reviewer: David Roe, Jeroen Demeyer

Merged: sage-5.1.beta2

Issue created by migration from https://trac.sagemath.org/ticket/12988

The text was updated successfully, but these errors were encountered:

saraedum · 2012-05-21T16:56:06Z

comment:1

I believe it is easiest to check that this is correct through the test framework of the categories.

I added a test to Rings and also one to Fields() checking that it's a prime or zero.

jdemeyer · 2012-05-26T06:05:57Z

Changed keywords from ZZ, characteristic to ZZ characteristic sd40.5

jdemeyer · 2012-05-26T06:05:57Z

Author: Julian Rueth

dandrake · 2012-05-26T17:12:08Z

comment:3

It seems like the test suite is not being run:

drake@sagenb:~/s/sage-5.1.beta0$ ./sage -t devel/sage/sage/categories/algebras_with_basis.py
sage -t  "devel/sage/sage/categories/algebras_with_basis.py"
**********************************************************************
File "/home/drake/s/sage-5.1.beta0/devel/sage/sage/categories/algebras_with_basis.py", line 60:
    sage: TestSuite(A).run(verbose=True)
Expected:
    running ._test_additive_associativity() . . . pass
    running ._test_an_element() . . . pass
    running ._test_associativity() . . . pass
    running ._test_category() . . . pass
    running ._test_characteristic() . . . pass
    running ._test_distributivity() . . . pass
    running ._test_elements() . . .
      Running the test suite of self.an_element()
      running ._test_category() . . . pass
      running ._test_eq() . . . pass
      running ._test_not_implemented_methods() . . . pass
      running ._test_pickling() . . . pass      pass
    running ._test_elements_eq() . . . pass
    running ._test_eq() . . . pass
    running ._test_not_implemented_methods() . . . pass
    running ._test_one() . . . pass
    running ._test_pickling() . . . pass
    running ._test_prod() . . . pass
    running ._test_some_elements() . . . pass
    running ._test_zero() . . . pass
Got:
    running ._test_additive_associativity() . . . pass
    running ._test_an_element() . . . pass
    running ._test_associativity() . . . pass
    running ._test_category() . . . pass
    running ._test_distributivity() . . . pass
    running ._test_elements() . . .
      Running the test suite of self.an_element()
      running ._test_category() . . . pass
      running ._test_eq() . . . pass
      running ._test_not_implemented_methods() . . . pass
      running ._test_pickling() . . . pass
      pass
    running ._test_elements_eq() . . . pass
    running ._test_eq() . . . pass
    running ._test_not_implemented_methods() . . . pass
    running ._test_one() . . . pass
    running ._test_pickling() . . . pass
    running ._test_prod() . . . pass
    running ._test_some_elements() . . . pass
    running ._test_zero() . . . pass

It's expecting to see the characteristic test, but that test is not run. I don't know the categories and test frameworks well enough to fix this. Do you see what's wrong?

saraedum · 2012-05-28T02:21:36Z

comment:4

That's strange. I'll run the doctests again to see if this also happens here.

Actually _test_characteristic didn't catch wrong characteristic() implementations in some cases which is related to #13043. I'll upload an updated patch soon.

saraedum · 2012-05-28T02:21:36Z

Dependencies: #13043

saraedum · 2012-05-28T13:45:06Z

Attachment: trac_12988.patch.gz

move characteristic() to the category of rings and check that it is in ZZ

dandrake · 2012-05-28T18:04:02Z

comment:6

This now passes doctests, and every example that I've tried successfully returns Integer characteristic. But I would like someone who understands the category framework and the test framework a bit better to look at this. Consider your patch to have a weak positive review.

roed314 · 2012-05-28T19:02:22Z

comment:7

This looks good to me.

jdemeyer · 2012-05-29T01:07:53Z

Reviewer: David Roe

jdemeyer · 2012-05-29T22:02:24Z

comment:9

3 doctest failures with sage-5.1.beta1:

sage -t  "devel/sage-main/sage/rings/padics/padic_base_leaves.py"
**********************************************************************
File "/usr/local/src/sage-5.1.beta1/devel/sage-main/sage/rings/padics/padic_base_leaves.py", line 168:
    sage: TestSuite(R).run()
Expected nothing
Got:
    Failure in _test_characteristic:
    Traceback (most recent call last):
      File "/usr/local/src/sage-5.1.beta1/local/lib/python/site-packages/sage/misc/sage_unittest.py", line 275, in run
        test_method(tester = tester)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python/site-packages/sage/categories/rings.py", line 258, in _test_characteristic
        tester.assertEqual(type(characteristic),sage.rings.integer.Integer)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python2.7/unittest/case.py", line 509, in assertEqual
        assertion_func(first, second, msg=msg)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python2.7/unittest/case.py", line 502, in _baseAssertEqual
        raise self.failureException(msg)
    AssertionError: <type 'int'> != <type 'sage.rings.integer.Integer'>
    ------------------------------------------------------------
    The following tests failed: _test_characteristic
**********************************************************************
File "/usr/local/src/sage-5.1.beta1/devel/sage-main/sage/rings/padics/padic_base_leaves.py", line 175:
    sage: TestSuite(R).run()
Expected nothing
Got:
    Failure in _test_characteristic:
    Traceback (most recent call last):
      File "/usr/local/src/sage-5.1.beta1/local/lib/python/site-packages/sage/misc/sage_unittest.py", line 275, in run
        test_method(tester = tester)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python/site-packages/sage/categories/rings.py", line 258, in _test_characteristic
        tester.assertEqual(type(characteristic),sage.rings.integer.Integer)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python2.7/unittest/case.py", line 509, in assertEqual
        assertion_func(first, second, msg=msg)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python2.7/unittest/case.py", line 502, in _baseAssertEqual
        raise self.failureException(msg)
    AssertionError: <type 'int'> != <type 'sage.rings.integer.Integer'>
    ------------------------------------------------------------
    The following tests failed: _test_characteristic
**********************************************************************
File "/usr/local/src/sage-5.1.beta1/devel/sage-main/sage/rings/padics/padic_base_leaves.py", line 182:
    sage: TestSuite(R).run()
Expected nothing
Got:
    Failure in _test_characteristic:
    Traceback (most recent call last):
      File "/usr/local/src/sage-5.1.beta1/local/lib/python/site-packages/sage/misc/sage_unittest.py", line 275, in run
        test_method(tester = tester)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python/site-packages/sage/categories/rings.py", line 258, in _test_characteristic
        tester.assertEqual(type(characteristic),sage.rings.integer.Integer)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python2.7/unittest/case.py", line 509, in assertEqual
        assertion_func(first, second, msg=msg)
      File "/usr/local/src/sage-5.1.beta1/local/lib/python2.7/unittest/case.py", line 502, in _baseAssertEqual
        raise self.failureException(msg)
    AssertionError: <type 'int'> != <type 'sage.rings.integer.Integer'>
    ------------------------------------------------------------
    The following tests failed: _test_characteristic
**********************************************************************

saraedum · 2012-05-30T01:51:11Z

Attachment: trac_12988_padic.patch.gz

fix characteristic for padics

jdemeyer · 2012-06-01T10:01:33Z

Changed reviewer from David Roe to David Roe, Jeroen Demeyer

jdemeyer · 2012-06-02T12:16:01Z

Merged: sage-5.1.beta2

saraedum added this to the sage-5.1 milestone May 21, 2012

saraedum added c: algebra labels May 21, 2012

saraedum assigned aghitza May 21, 2012

saraedum added the s: needs review label May 21, 2012

dandrake added s: needs work and removed s: needs review labels May 26, 2012

saraedum added s: needs review and removed s: needs work labels May 28, 2012

roed314 added s: positive review and removed s: needs review labels May 28, 2012

jdemeyer added s: needs work and removed s: positive review labels May 29, 2012

saraedum added s: needs review and removed s: needs work labels May 30, 2012

jdemeyer removed the s: needs review label Jun 1, 2012

jdemeyer added the s: positive review label Jun 1, 2012

jdemeyer removed the s: positive review label Jun 2, 2012

jdemeyer closed this as completed Jun 2, 2012

burcin mentioned this issue Dec 6, 2012

Full interface to letterplace from singular #7797

Closed

saraedum mentioned this issue Jun 6, 2012

is_squarefree() incorrect over imperfect fields #12404

Closed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

characteristic() should be an integer #12988

characteristic() should be an integer #12988

saraedum commented May 21, 2012

saraedum commented May 21, 2012

jdemeyer commented May 26, 2012

jdemeyer commented May 26, 2012

dandrake commented May 26, 2012

saraedum commented May 28, 2012

saraedum commented May 28, 2012

saraedum commented May 28, 2012

dandrake commented May 28, 2012

roed314 commented May 28, 2012

jdemeyer commented May 29, 2012

jdemeyer commented May 29, 2012

saraedum commented May 30, 2012

jdemeyer commented Jun 1, 2012

jdemeyer commented Jun 2, 2012

characteristic() should be an integer #12988

characteristic() should be an integer #12988

Comments

saraedum commented May 21, 2012

saraedum commented May 21, 2012

jdemeyer commented May 26, 2012

jdemeyer commented May 26, 2012

dandrake commented May 26, 2012

saraedum commented May 28, 2012

saraedum commented May 28, 2012

saraedum commented May 28, 2012

dandrake commented May 28, 2012

roed314 commented May 28, 2012

jdemeyer commented May 29, 2012

jdemeyer commented May 29, 2012

saraedum commented May 30, 2012

jdemeyer commented Jun 1, 2012

jdemeyer commented Jun 2, 2012