Robert Bradshaw wrote:
> On Aug 22, 2009, at 3:13 AM, Mani chandra wrote:
>
>
>> Mani chandra wrote:
>>
>>> Hi,
>>>
>>> How does one define a variable in sage and make sure the it's
>>> conjugate is the same as the variable itself?
>>>
>>> Thanks,
>>> Mani chandra
>>>
>>>
>>>
>> Hi,
>>
>> Perhaps I wasn't specific.
>>
>> sage: var('a')
>> sage: a.conjugate()
>> conjugate(a)
>>
>> What I want is for SAGE to return a, instead of conjugate(a). Does
>> "var"
>> take any arguments that forces a variable to be real?
>>
>
> You have to invoke simplify for it to look at assumptions.
>
> sage: var('a')
> sage: assume(a, 'real')
> sage: a.conjugate().simplify()
> a
>
> - Robert
>
>
> >
>
>
There seems to be something wrong with this implementation:
sage: var('a, b')
(a, b)
sage: assume(a, 'real')
sage: assume(b, 'real')
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
/home/mc/<ipython console> in <module>()
/opt/sage/sage/local/lib/python2.6/site-packages/sage/symbolic/assumptions.pyc
in assume(*args)
194 else:
195 try:
--> 196 x.assume()
197 except KeyError:
198 raise TypeError, "assume not defined for objects
of type '%s'"%type(x)
/opt/sage/sage/local/lib/python2.6/site-packages/sage/symbolic/assumptions.pyc
in assume(self)
96 maxima.set("context", cur)
97
---> 98 if not self in _assumptions:
99 maxima.activate(self._context)
100 _assumptions.append(self)
/opt/sage/sage/local/lib/python2.6/site-packages/sage/symbolic/assumptions.pyc
in __cmp__(self, other)
70 if isinstance(self, GenericDeclaration) and
isinstance(other, GenericDeclaration):
71 return cmp( (self._var, self._assumption),
---> 72 (other._var, other._assumption) )
73 else:
74 return cmp(type(self), type(other))
/opt/sage/sage/local/lib/python2.6/site-packages/sage/symbolic/expression.so
in sage.symbolic.expression.Expression.__nonzero__
(sage/symbolic/expression.cpp:7506)()
AttributeError: 'GenericDeclaration' object has no attribute 'variables'
Looks like it can define only one variable in the namespace as real.
This is pretty strange.
--Mani chandra
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to sage-support@googlegroups.com
To unsubscribe from this group, send email to
sage-support-unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/sage-support
URLs: http://www.sagemath.org
-~----------~----~----~----~------~----~------~--~---
