Failing weak order assertion on random symbolic expression

[gh-kliem]

File "src/sage/symbolic/random_tests.py", line 430, in sage.symbolic.random_tests.test_symbolic_expression_order
Failed example:
    test_symbolic_expression_order(10000)  # long time
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/doctest/forker.py", line 718, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/doctest/forker.py", line 1137, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.symbolic.random_tests.test_symbolic_expression_order[2]>", line 1, in <module>
        test_symbolic_expression_order(Integer(10000))  # long time
      File "/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/symbolic/random_tests.py", line 456, in test_symbolic_expression_order
        assert_strict_weak_order(a, b, c, mixed_order)
      File "/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/symbolic/random_tests.py", line 387, in assert_strict_weak_order
        cmp_M[i, j] = (cmp_func(x[i], x[j]) == 1)   # or -1, doesn't matter
      File "sage/symbolic/comparison.pyx", line 228, in sage.symbolic.comparison.mixed_order (build/cythonized/sage/symbolic/comparison.cpp:4349)
        cpdef int mixed_order(lhs, rhs) except -2:
      File "sage/symbolic/comparison.pyx", line 268, in sage.symbolic.comparison.mixed_order (build/cythonized/sage/symbolic/comparison.cpp:4126)
        less_than = _mixed_key(lhs) < _mixed_key(rhs)
      File "sage/symbolic/comparison.pyx", line 355, in sage.symbolic.comparison._mixed_key.__lt__ (build/cythonized/sage/symbolic/comparison.cpp:5238)
        return det_ex < 0
    TypeError: '<' not supported between instances of 'Pi' and 'int'
**********************************************************************
1 item had failures:
   2 of   4 in sage.symbolic.random_tests.test_symbolic_expression_order
    [49 tests, 2 failures, 3.59 s]

The underlying problem is the following:

sage: pi = sage.symbolic.constants.Pi()                                                                                                                                                                                                                                                                                                                                    
sage: pi < 0                                                                                                                                                                                                                                                                                                                                                               
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-7-f23f08971c70> in <module>
----> 1 pi < Integer(0)

/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/rings/integer.pyx in sage.rings.integer.Integer.__richcmp__ (build/cythonized/sage/rings/integer.c:7888)()
    947             c = mpz_cmp_d((<Integer>left).value, d)
    948         else:
--> 949             return coercion_model.richcmp(left, right, op)
    950 
    951         return rich_to_bool_sgn(op, c)

/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/structure/coerce.pyx in sage.structure.coerce.CoercionModel.richcmp (build/cythonized/sage/structure/coerce.c:20854)()
   2006             raise bin_op_exception('<=', x, y)
   2007         elif op == Py_GT:
-> 2008             raise bin_op_exception('>', x, y)
   2009         else:
   2010             raise bin_op_exception('>=', x, y)

TypeError: unsupported operand parent(s) for >: 'Integer Ring' and '<class 'sage.symbolic.constants.Pi'>'

[mjo]

I wasn't able to reproduce the failure, but I'm pretty sure that Pi is arising from pi.pyobject() during the comparison. In any case, it looks like I've fixed at least one bug. I'll test the new branch overnight.

---

New commits:

​1ab9784	Trac #32243: patch gfan to look for cddlib headers in new location.
​cfab03a	Trac #32243: look for cddlib-0.94m headers in the right place.
​b30ce37	Trac #32185: special case constant symbolic relations.

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​551d3ae

Trac #32185: special case constant symbolic relations.

[mjo]

Tests pass. I dropped the two commits from #32243 that I left in there by mistake.

[tscrim]

LGTM.