William Stein wrote: > 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 >> >> > > > > Hi, I forgot to add hardware info. The program is using nowhere close to the 4 GB limit on my computer. I'm using Archlinux x86_64, kernel 2.6.30. I also tried it on another machine which has 1 GB of ram (which also is not being used fully) and which has Archlinux x86_64, kernel 2.6.28 .
I totally agree that symbolic calculus backend be changed from Maxima to whatever is the best out there. I've had so many (other)troubles with Maxima in SAGE, with "assume", "solve", etc... As it stands, It simply is not an elegant system. Mani chandra --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
