On Tue, Apr 3, 2012 at 11:29 AM, L. Barrott <lb489@cam.ac.uk> wrote:
On Tue, Apr 3, 2012 at 5:54 AM, L. Barrott <lb489@cam.ac.uk> wrote:
Hello,
I have been trying to get scipy to solve a set of coupled odes and in particular I want to use the dopri 45 method as I want to compare the results to the ode45 method in MATLAB. The code runs along the lines of:
def func (t, Y, params): ... return (Ydot)
with Y a vector. The other ode methods (except dop853 of course) solve this fine but even if I use the example code on the documentation page the dopri method returns the following error
create_cb_arglist: Failed to build argument list (siz) with enough arguments (tot-opt) required by user-supplied function (siz,tot,opt=2,3,0). ...(traceback stuff) _dop.error: failed in processing argument list for call-back fcn.
Any ideas where I am going wrong?
Many thanks LB
It would help to see more of your code. Could you include a complete, self-contained script that demonstrates the error?
Warren
Even something as simple as;
from scipy.integrate import ode y0, t0 = [0, 1], 0 def func (t, y, x): return [x, y[0]] r = ode(func).set_integrator ('dopri5') r.set_initial_value(y0, t0).set_f_params(1) t1 = 10 dt = 0.1 while r.successful() and r.t < t1: r.integrate(r.t+dt)
Will fail and this is lifted straight from the documentation as far as I can see. The full error message is
create_cb_arglist: Failed to build argument list (siz) with enough arguments (tot-opt) required by user-supplied function (siz,tot,opt=2,3,0). Traceback (most recent call last): File "<stdin>", line 2, in <module> File "/usr/lib/python2.7/dist-packages/scipy/integrate/ode.py", line 326, in integrate self.f_params,self.jac_params) File "/usr/lib/python2.7/dist-packages/scipy/integrate/ode.py", line 745, in run x,y,iwork,idid = self.runner(*((f,t0,y0,t1) + tuple(self.call_args))) _dop.error: failed in processing argument list for call-back fcn.
LB
I suspect you are using version 0.9 (or earlier) of scipy. This looks like a bug that was fixed in 0.10: http://projects.scipy.org/scipy/ticket/1392 Warren