On Aug 5, 12:07 pm, Nils Bruin <[email protected]> wrote:
> On Aug 5, 8:41 am, Jose Guzman <[email protected]> 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.
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