Another one from the notebook's report a problem bugtracker about ODEs:
assume(n, 'integer') causes desolve to fail
Here is the code that fails :
var('t n')
assume(n, 'integer')
f = function('f',t)
ode = diff(f,t) + (-1)^n*f == 0
desolve(ode, f, [0,1], t)
It should do the same as :
var('t n')
f = function('f',t)
ode = diff(f,t) + (-1)^n*f == 0
desolve(ode, f, [0,1], t)
Confirmed by me in 4.1.1, traceback:
sage: var('t n')
(t, n)
sage: assume(n, 'integer')
sage: f = function('f',t)
sage: ode = diff(f,t) + (-1)^n*f == 0
sage: desolve(ode, f, [0,1], t)
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
/home/schilly/<ipython console> in <module>()
/usr/local/sage/local/lib/python2.6/site-packages/sage/calculus/desolvers.pyc
in desolve(de, dvar, ics, ivar)
111 if ics is not None:
112 if len(ics) == 2:
--> 113 ics = to_eqns([ivar, dvar], ics)
114 soln = soln.ic1(ics[0], ics[1])
115 if len(ics) == 3:
/usr/local/sage/local/lib/python2.6/site-packages/sage/calculus/desolvers.pyc
in to_eqns(lhs, exprs)
104 eqns.append(expr)
105 else:
--> 106 if lhs == dvar and len(exprs) == 2:
107 ivar_ic = exprs[0] # figure this out...
108 lhs = lhs.subs(lhs.default_variable()==ivar_ic)
/usr/local/sage/local/lib/python2.6/site-packages/sage/symbolic/expression.so
in sage.symbolic.expression.Expression.__nonzero__
(sage/symbolic/expression.cpp:7553)()
AttributeError: 'GenericDeclaration' object has no attribute 'variables'
H
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send an email to [email protected]
To unsubscribe from this group, send an email to
[email protected]
For more options, visit this group at http://groups.google.com/group/sage-devel
URLs: http://www.sagemath.org
-~----------~----~----~----~------~----~------~--~---
