Mhh, interesting.
In the REPL it works:
A=matrix([[0,0,0,0],[1/2,0,0,0],[0,1/2,0,0],[0,0,1,0]])*AA.one()
ok
and:
sage: A.parent().is_exact()
True
But an other problem happens:
The class "RungeKutta" (the parent class of RK4) as a test:
class RungeKutta(SageObject):
def __init__(self,A,B,Title,C=[]):
if not A.parent().is_exact():
<raise an Exception">
and I get the exception, which seems to mean that, seen from the
RungeKutta class the parent af A is not exact.
Then putting a
print(A.parent())
just before the test in the constructor of RungeKutta, I get:
Full MatrixSpace of 4 by 4 dense matrices over Real Double Field
which, for me, is very surprising... why ?
Thank you!
thierry
Le 21/04/2025 à 11:05, pedritomele...@gmail.com a écrit :
Hi,
I would do
A=matrix([[0,0,0,0],[1/2,0,0,0],[0,1/2,0,0],[0,0,1,0]])*AA.one()
B=vector([1/6,2/6,2/6,1/6])*AA.one()
Best, Pedro
El lun, 21 abr 2025 a las 10:35, Thierry Dumont (<tdum...@math.univ-
lyon1.fr <mailto:tdum...@math.univ-lyon1.fr>>) escribió:
May be this problem is trivial (RTFM...) but:
1) Suppose I run this in the REPL:
from sage.all import *
from rkkit.RKRungeKutta import * #my code
class RK4(RungeKutta):
def __init__(self):
title="Classical Runge-Kutta 4 explicit method"
A=matrix(AA,[[0,0,0,0],[1/2,0,0,0],[0,1/2,0,0],[0,0,1,0]])
B=vector(AA,[1/6,2/6,2/6,1/6])
super().__init__(A,B,title)
then I can do:
R=RK4()
everything is ok.
2) Now, in a directory "methods" I put the same piece of code as above
in a file called "RK4.py".
I add a file __init__.py in methods/, which is:
from sage.all import *
from rkkit.RKRungeKutta import *
__all__=["RK4"]
So, I have
methods/
__init__.py
RK4.py
Now, typing:
from methods import *
R=RK4.RK4()
I get the error message:
typeError: Illegal initializer for algebraic number
How can I avoid this?
(something like putting Integer() around the elements of the list in
matrix(AA,[[0,0,0,0],[1/2,0,0,0],[0,1/2,0,0],[0,0,1,0]])
is something I want (need) to avoid).
Yours,
Thierry
--
You received this message because you are subscribed to the Google
Groups "sage-support" group.
To unsubscribe from this group and stop receiving emails from it,
send an email to sage-support+unsubscr...@googlegroups.com
<mailto:sage-support%2bunsubscr...@googlegroups.com>.
To view this discussion visit https://groups.google.com/d/msgid/
sage-support/9fbe6b5b-1bd1-4bf2-bc66-ee0ff7343826%40math.univ-
lyon1.fr <https://groups.google.com/d/msgid/sage-
support/9fbe6b5b-1bd1-4bf2-bc66-ee0ff7343826%40math.univ-lyon1.fr>.
--
You received this message because you are subscribed to the Google
Groups "sage-support" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to sage-support+unsubscr...@googlegroups.com <mailto:sage-
support+unsubscr...@googlegroups.com>.
To view this discussion visit https://groups.google.com/d/msgid/sage-
support/
CAOAJP6qRM47LOaFx_nQhmubGELzfj_f8ASkQfP%3D5aZkG2DOSdA%40mail.gmail.com
<https://groups.google.com/d/msgid/sage-support/
CAOAJP6qRM47LOaFx_nQhmubGELzfj_f8ASkQfP%3D5aZkG2DOSdA%40mail.gmail.com?
utm_medium=email&utm_source=footer>.
--
You received this message because you are subscribed to the Google Groups
"sage-support" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-support+unsubscr...@googlegroups.com.
To view this discussion visit
https://groups.google.com/d/msgid/sage-support/b5590e4a-7628-4782-9bde-0cc96f39151b%40math.univ-lyon1.fr.
