2009/4/16 Jason Grout <jason-s...@creativetrax.com>:
>
> Ondrej Certik wrote:
>> Hi,
>>
>> I would expect this to work:
>>
>> sage: e = integrate(sqrt(x**3+1), x, 2, 10)
>> sage: e.n()
>> ---------------------------------------------------------------------------
>> TypeError Traceback (most recent call last)
>>
>> /home/ondrej/<ipython console> in <module>()
>>
>> /home/ondrej/ext/sage-3.4.1.alpha0/local/lib/python2.5/site-packages/sage/calculus/calculus.pyc
>> in numerical_approx(self, prec, digits)
>> 1514 except TypeError:
>> 1515 # try to return a complex result
>> -> 1516 approx = self._complex_mpfr_field_(ComplexField(prec))
>> 1517
>> 1518 return approx
>>
>> /home/ondrej/ext/sage-3.4.1.alpha0/local/lib/python2.5/site-packages/sage/calculus/calculus.pyc
>> in _complex_mpfr_field_(self, field)
>> 1748
>> 1749 def _complex_mpfr_field_(self, field):
>> -> 1750 raise TypeError
>> 1751
>> 1752 def _complex_double_(self, C):
>>
>> TypeError:
>>
>>
>>
>> am I doing it the wrong way? With sympy:
>>
>>
>> sage: from sympy import var, integrate
>> sage: var("x")
>> x
>> sage: e = integrate(sqrt(x**3+1), (x, 2, 10))
>> sage: e.n()
>> 124.616199194723
>>
>>
>
>
> You didn't do anything wrong. It should work.
I wouldn't necessarily say it "should work", since I'm sure nobody
implementing functionality so it should work, and it doesn't work like
this in Maxima (which Sage is just calling for this):
%maxima
integrate(sqrt(x^3+1),x,2,10), float
///
'integrate((x^3+1)^0.5,x,2,10)
It would be very nice to have this feature though!
-- William
>
> See http://trac.sagemath.org/sage_trac/ticket/3863 for the same error.
> This has also come up in discussion recently (see the end of
> http://groups.google.com/group/sage-support/browse_thread/thread/65e7983e80a983e9/2cdd45aff55425d2?lnk=gst&q=numerical_approx+integral#2cdd45aff55425d2)
>
> Of course, the work around is to use nintegrate. But I agree that what
> you did should work. So...does anyone have a patch?
>
> Jason
>
>
> --
> Jason Grout
>
>
> >
>
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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