Trac #34254: 32-bit failure in src/sage/symbolic/expression.pyx

Possibly caused by the Singular to 4.3.1 update
{{{
sage -t --random-seed=210332952936240496895287497988069989916
src/sage/symbolic/expression.pyx
**********************************************************************
File "src/sage/symbolic/expression.pyx", line 12881, in
sage.symbolic.expression.Expression._plot_fast_callable
Failed example:
    f(10) == abs((I*10+1)^4)
Expected:
    True
Got:
    False
**********************************************************************
1 item had failures:
   1 of   9 in sage.symbolic.expression.Expression._plot_fast_callable
    [3072 tests, 1 failure, 39.49 s]
----------------------------------------------------------------------
sage -t --random-seed=210332952936240496895287497988069989916
src/sage/symbolic/expression.pyx  # 1 doctest failed
----------------------------------------------------------------------
}}}
Apparently numerical noise:
{{{
sage: x = var('x', domain='real')
....: s = abs((1+I*x)^4)
....: f = s._plot_fast_callable(x)
....: f(10) == abs((I*10+1)^4)
....:
False
sage: f(10)
10200.999999999998
sage: abs((I*10+1)^4)
....:
10201
}}}

URL: https://trac.sagemath.org/34254
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s): Matthias Koeppe

src/sage/symbolic/expression.pyx

@@ -12878,7 +12878,7 @@ cdef class Expression(Expression_abc):
             sage: x = var('x', domain='real')
             sage: s = abs((1+I*x)^4)
             sage: f = s._plot_fast_callable(x)
-            sage: f(10) == abs((I*10+1)^4)
+            sage: abs(f(10) - abs((I*10+1)^4)) < 1e-11
             True
             sage: plot(s)
             Graphics object consisting of 1 graphics primitive