#10142: Frequent crash in ode_solver
------------------------------+---------------------------------------------
Reporter: mister.wardrop | Owner: burcin
Type: defect | Status: new
Priority: critical | Milestone:
Component: calculus | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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I have been using Sagemath (several versions, but must recently, 4.5.2;
but this bug existed in previous versions as well) for my Honours thesis
in quantum mechanics, and have been making heavy use of the integration
routines. The ode_solver regularly crashes for specific step-sizes. I have
not been able to work out a systematic pattern, but if it doesn't work
once, it continues not to work no matter how many times you try. It can
crash for any step size; sometimes even for integers. It does, however,
usually only crash on the final step. It also seems to be independent of
the numerical solver.
When it crashes, it reports something like:
ERROR: An unexpected error occurred while tokenizing input[[BR]]The
following traceback may be corrupted or invalid[[BR]]The error message is:
('EOF in multi-line statement', (60,
0))[[BR]][[BR]]---------------------------------------------------------------------------[[BR]]!ValueError
Traceback (most recent call
last)[[BR]][[BR]]/home/themadhatter/Honours/modelling/<ipython console> in
<module>()[[BR]][[BR]]/home/themadhatter/Honours/modelling/lib/sequences.pyc
in evolution(self, period, step, perturbations, carryon)[[BR]] 16
[[BR]] 17 def
evolution(self,period=100,step=1,perturbations=None,carryon=False):[[BR]]--->
18 return
self.SYSTEM.integrate_numerically(perturbation=perturbations,self_entangle=True,step=step,period=period,projector=self.PROJECTOR,time_dependence=self.TIME_DEPENDENCE,carryon=carryon)[[BR]]
19 [[BR]] 20 def
fidelity(self,period=100,step=1,perturbations=None,carryon=False):[[BR]][[BR]]/home/themadhatter/Honours/modelling/lib/hamiltonian.pyc
in integrate_numerically(self, y_0, period, step, perturbations,
error_rel, error_abs, self_entangle, projector, time_dependence, function,
increase_dim, noise, carryon, **params)[[BR]] 560
else:[[BR]] 561 integrator =
self.Integrator(self,y_0,self_entangle=self_entangle,noise=noise,increase_dim=increase_dim,perturbations=perturbations,time_dependence=time_dependence,cache='numerical',error_rel=error_rel,error_abs=error_abs)[[BR]]-->
562 return integrator.start(period,step)[[BR]] 563
#[[BR]] 564 # Integrate a given initial state using the Hamiltonian
and compare to ideal
evolution[[BR]][[BR]]/home/themadhatter/Honours/modelling/lib/hamiltonian.pyc
in start(self, period, step)[[BR]] 521 [[BR]] 522
def start(self,period=100,step=1):[[BR]]--> 523 self.results =
self.integrate(self.y_0,period=period,step=step)[[BR]] 524
if self.multiple:[[BR]] 525 return
self.results[[BR]][[BR]]/home/themadhatter/Honours/modelling/lib/hamiltonian.pyc
in integrate(self, y_0, period, step, t_offset)[[BR]] 512
[[BR]] 513 for y_0 in y_0s:[[BR]]--> 514
T.ode_solve(y_0=y_0,t_span=[0,period],params=params,num_points=int(period/step))[[BR]]
515 results.append(T.solution)[[BR]] 516
pb_run+=1[[BR]][[BR]]/home/themadhatter/sage/local/lib/python2.6/site-
packages/sage/gsl/ode.so in sage.gsl.ode.ode_solver.ode_solve
(sage/gsl/!ode.c:4558)() [[BR]][[BR]]!ValueError: error solving
I have been very careful in checking my code, and am confident that it is
not a fault in my code. I have been working around it by changing the
step-size adhoc... but when doing a series of runs; it is VERY annoying.
><
If you need more information, let me know. I am quite happy to give you my
entire code; along with specific instructions on how to trigger the crash.
Please fix this!
Kind Regards,[[BR]]Matthew
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10142>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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