On Sat, Aug 15, 2009 at 5:44 AM, Mani chandra<mchan...@iitk.ac.in> wrote: > Hi, > > I wrote a code in sage to construct a Low Dimensional model for the > Magnetohydrodynamic equations to study dynamos etc... But the program > crashes at different points on different machines with the following error: > > Traceback (most recent call last): > File "./LowD_model.py", line 158, in <module> > du_x_dt.append(select_mode(RHS_Ux, l, m, n) ) > File "./LowD_model.py", line 28, in select_mode > val = (func*exp(-I*(l*x + m*y + > n*z))).integrate(x,0,2*pi).integrate(y,0,2*pi).integrate(z,0,2*pi) > File "expression.pyx", line 5700, in > sage.symbolic.expression.Expression.integral > (sage/symbolic/expression.cpp:24436) > File > "/opt/sage/sage/local/lib/python2.6/site-packages/sage/calculus/calculus.py", > line 566, in integral > result = expression._maxima_().integrate(v, a, b) > File > "/opt/sage/sage/local/lib/python2.6/site-packages/sage/interfaces/maxima.py", > line 2003, in integral > return I(var, min, max) > File > "/opt/sage/sage/local/lib/python2.6/site-packages/sage/interfaces/expect.py", > line 1382, in __call__ > return self._obj.parent().function_call(self._name, [self._obj] + > list(args), kwds) > File > "/opt/sage/sage/local/lib/python2.6/site-packages/sage/interfaces/expect.py", > line 1290, in function_call > return self.new(s) > File > "/opt/sage/sage/local/lib/python2.6/site-packages/sage/interfaces/expect.py", > line 1086, in new > return self(code) > File > "/opt/sage/sage/local/lib/python2.6/site-packages/sage/interfaces/expect.py", > line 1021, in __call__ > return cls(self, x, name=name) > File > "/opt/sage/sage/local/lib/python2.6/site-packages/sage/interfaces/expect.py", > line 1425, in __init__ > raise TypeError, x > TypeError: Error executing code in Maxima > CODE: > sage2436 : integrate(sage2432,sage2433,sage2434,sage2435)$ > Maxima ERROR: > > Maxima encountered a Lisp error: > > Memory limit reached. Please jump to an outer point or quit program. > > Automatically continuing. > To reenable the Lisp debugger set *debugger-hook* to nil. > > > I'm attaching the entire code but the function where it crashed is the > follows: > > def select_mode(func,l,m,n): > val = (func*exp(-I*(l*x + m*y + > n*z))).integrate(x,0,2*pi).integrate(y,0,2*pi).integrate(z,0,2*pi) > return val/(8*pi**3) > > Also, I'd like to know if the symbolic computation backend for SAGE is > Maxima, Pynac or Sympy? Or is it a combination of all the three?
All three, though I don't think anything from sympy is used by default. > Will > SAGE move to a single backend in the future? It will be much better if Sage moves away from Maxima, as your question nicely illustrates. Here's a big shout of encouragement to everybody out there who is working on code to make it so Sage doesn't depend at all on Maxima for symbolic calculus. > If this bug can't be fixed, > is it suggested that I rewrite the code using the Sympy library? > Is it really a bug? It says "Memory limit reached." Running out of memory isn't necessarily a bug. Computers have finite RAM. What operating system, computer hardware, etc. are you using? Without that info it is very hard to be more helpful. > P.S If anyone is running the code, then please note that it takes a LOT > of time. > > Thanking you, > Mani chandra > > > > -- William Stein Associate Professor of Mathematics University of Washington http://wstein.org --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
