On 05/08/11 18:20, kcrisman wrote:
On Aug 5, 12:07 pm, Nils Bruin<nbr...@sfu.ca> wrote:
On Aug 5, 8:41 am, Jose Guzman<sjm.guz...@googlemail.com> wrote:
In either case, Sage returns the same error:
TypeError: unable to make sense of Maxima expression
'v(t)=-e^-(t*gL/cm)*(at(integrate((EL*gL+signum(t-5)-signum(t-13))*e^(t*gL/
cm),t),[t=0,v(t)=-65])-integrate((EL*gL+signum(t-5)-signum(t-13))*e^(t*gL/c
m),t)+65*cm)/cm'
in Sage
That seems a bug to me. It is probably because maxima's "at" function
Hmm. Maxima's at function IS translated, as you can see in that the
final error has 'at' in it. In calculus.py:
delayed_functions = maxima_qp.findall(s)
if len(delayed_functions)> 0:
for X in delayed_functions:
if X == '?%at': # we will replace Maxima's "at" with
symbolic evaluation, not an SFunction
pass
else:
syms[X[2:]] = function_factory(X[2:])
s = s.replace("?%","")
Probably the problem is that this was too naive. The thing you did
with M(expr).sage() bypasses this, because this 'at' is not
universally imported into the global namespace. Maybe it should be?
- kcrisman
similar functionality is available in the form of "substitute" and
"call". Here is a more direct way of arriving at a similar error
(requires 4.7.1 for interfacing with the LISP below, but that should
not be essential for exposing the problem):
sage: M=sage.calculus.calculus.maxima
sage: E=sage.libs.ecl.ecl_eval
sage: expr=E("#$at(derivative(f(x),x),[x=0])$")
sage: M(expr)
?%at('diff(f(x),x,1),[x=0])
sage: M(expr).sage()
[...]
TypeError: unable to make sense of Maxima expression 'at(diff(f(x),x,
1),[x=0])' in Sage
You can help sage by filing a bug report.
I would be willing to 1) submit a bug report, and even 2) try to solve
it if somebody would assist me with whole process of submitting a track
(maybe in #sagemath channel on freenode. That would be a fantastic
opportunity to collaborate with the Sage development. I would be very
happy to have the option of integrating this kind of functions in Sage.
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