And, BTW:
sage: maxima(t)
(%i/(10*%pi))^(3/2)
sage: maxima(t)^2
-%i/(1000*%pi^3)
HTH,...
Le jeudi 17 octobre 2019 08:53:47 UTC+2, Emmanuel Charpentier a écrit :
>
> It's worse than that...
>
> sage: t=((1/10)*I/pi)^(3/2)
> sage: t
> (1/10*I/pi)^(3/2)
> sage: t^2
>
> This doesn't return. An I had to insist to interrupt (had to strike C-C 6
> times in emacs' sage-shell-mode...)
>
>
> ^C^C^C^C^C^C---------------------------------------------------------------------------
> KeyboardInterrupt Traceback (most recent call last)
> <ipython-input-31-f00da4fd424a> in <module>()
> ----> 1 t**Integer(2)
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/structure/element.pyx
>
> in sage.structure.element.Element.__pow__
> (build/cythonized/sage/structure/element.c:14088)()
> 2038 return (<Element>left)._pow_(right)
> 2039 if BOTH_ARE_ELEMENT(cl):
> -> 2040 return coercion_model.bin_op(left, right, pow)
> 2041
> 2042 cdef long value
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/structure/coerce.pyx
>
> in sage.structure.coerce.CoercionModel.bin_op
> (build/cythonized/sage/structure/coerce.c:9800)()
> 1153 return (<Action>action)._act_(x, y)
> 1154 else:
> -> 1155 return (<Action>action)._act_(y, x)
> 1156
> 1157 # Now coerce to a common parent and do the operation there
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/structure/coerce_actions.pyx
>
> in sage.structure.coerce_actions.IntegerPowAction._act_
> (build/cythonized/sage/structure/coerce_actions.c:10173)()
> 861 integer_check_long(n, &value, &err)
> 862 if not err:
> --> 863 return e._pow_long(value)
> 864 return e._pow_int(n)
> 865
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/structure/element.pyx
>
> in sage.structure.element.Element._pow_long
> (build/cythonized/sage/structure/element.c:14635)()
> 2115 Generic path for powering with a C long.
> 2116 """
> -> 2117 return self._pow_int(n)
> 2118
> 2119
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/symbolic/expression.pyx
>
> in sage.symbolic.expression.Expression._pow_int
> (build/cythonized/sage/symbolic/expression.cpp:25386)()
> 4049 pi^4
> 4050 """
> -> 4051 return self._pow_(self._parent(other))
> 4052
> 4053 def derivative(self, *args):
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/symbolic/expression.pyx
>
> in sage.symbolic.expression.Expression._pow_
> (build/cythonized/sage/symbolic/expression.cpp:25211)()
> 4033 relational_operator(self._gobj))
> 4034 else:
> -> 4035 x = g_pow(self._gobj, nexp._gobj)
> 4036 return new_Expression_from_GEx(self._parent, x)
> 4037
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/rings/number_field/number_field_element.pyx
>
> in sage.rings.number_field.number_field_element.NumberFieldElement.__pow__
> (build/cythonized/sage/rings/number_field/number_field_element.cpp:22076)()
> 2316 if (isinstance(base, NumberFieldElement) and
> 2317 (isinstance(exp, Integer) or type(exp) is int or exp
> in ZZ)):
> -> 2318 return generic_power(base, exp)
> 2319
> 2320 if (isinstance(base, NumberFieldElement) and exp in QQ):
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/arith/power.pyx
> in sage.arith.power.generic_power
> (build/cythonized/sage/arith/power.c:2376)()
> 81 raise NotImplementedError("non-integral exponents not
> supported")
> 82 if not err:
> ---> 83 return generic_power_long(a, value)
> 84
> 85 if n < 0:
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/arith/power.pyx
> in sage.arith.power.generic_power_long
> (build/cythonized/sage/arith/power.c:2663)()
> 100 u = -u
> 101 a = invert(a)
> --> 102 return generic_power_pos(a, u)
> 103
> 104
>
> /usr/local/sage-P3-2/local/lib/python3.7/site-packages/sage/arith/power.pyx
> in sage.arith.power.generic_power_pos
> (build/cythonized/sage/arith/power.c:2796)()
> 118 n >>= 1
> 119 while n:
> --> 120 sig_check()
> 121 apow *= apow
> 122 if n & 1:
>
> KeyboardInterrupt:
> sage:
>
> This, IMNSHO, is a (quite serious) bug, affecting a very basic
> functionality of Sage.
>
> That's why I have opened Trac#28620
> <https://trac.sagemath.org/ticket/28620#ticket> against "symbolics", and
> flagged it as "critical"
>
> HTH,
>
>
>
> Le mardi 15 octobre 2019 17:17:41 UTC+2, Dima Pasechnik a écrit :
>>
>> On Tue, Oct 15, 2019 at 3:57 PM 'Florian Hanisch' via sage-devel
>> <sage-...@googlegroups.com> wrote:
>> >
>> > Hi,
>> >
>> > this might be a duplicate (sorry) but I could not find this issue
>> described anywhere else. I have been running the code
>> >
>> > k=1.0
>> > (I*k/(2*pi*5))^(6/2)
>> >
>> > and got the result
>> >
>> > (1.00000046096651e-4294967297*I)/pi^3
>> >
>> > This is clearly way too small, adding CC(...) to get a numerical value
>> does not resolve
>> > the problem. However, simply replacing 6/2 by 3 yields the correct
>> result:
>> >
>> > (I*k/(2*pi*5))^(3)
>> > result: -0.00100000000000000*I/pi^3
>> >
>> > Did I make some stupid and obvious error or is this just a strange bug
>> ? I am using
>> > sage 8.6 (jupyter notebook) on a linux computer (Centos 7, 64 bit). I
>> tried these code
>> > snippets on cocalc and ran into the same problems. Friends of mine have
>> also reported the
>> > problem on sage 8.8.
>>
>> yes, it appears to be a bug. here is a slightly easier example:
>>
>> sage: t
>> (0.100000000000000*I/pi)^(3/2)
>> sage: t.n()^2
>> -6.77626357803440e-21 - 0.0000322515344331995*I
>> sage: t.n()
>> # a correct numerical value
>> -0.00401569012955429 + 0.00401569012955429*I
>> sage: t^2
>> # pynac bug ?
>> (1.00000046096651e-4294967297*I)/pi^3
>>
>> maxima is doing it right:
>>
>> sage: maxima(t)
>> ((0.1*%i)/%pi)^(3/2)
>> sage: maxima(t)^2
>> -(0.001*%i)/%pi^3
>>
>>
>>
>>
>> >
>> > Thanks a lot,
>> >
>> > Florian
>> >
>> >
>> >
>> > --
>> > You received this message because you are subscribed to the Google
>> Groups "sage-devel" group.
>> > To unsubscribe from this group and stop receiving emails from it, send
>> an email to sage-...@googlegroups.com.
>> > To view this discussion on the web visit
>> https://groups.google.com/d/msgid/sage-devel/ba2015a4-6249-4d4b-98ce-5d8e115fd95a%40googlegroups.com.
>>
>>
>>
>
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