[SciPy-User] scipy.optimize.fixed_point -- TypeError: can't multiply sequence by non-int of type 'float'
Warren Weckesser
warren.weckesser@enthought....
Wed Sep 5 07:33:05 CDT 2012
On Tue, Sep 4, 2012 at 2:06 PM, Ted To <rainexpected@theo.to> wrote:
> Hi,
>
> I'm having trouble figuring out what I'm doing wrong here. I have a
> function br(p,q) defined where p and q are lists of length 2 and I'm
> trying to compute the fixed point of br for a given q. E.g.,
> fixed_point(br,x0=p,args=(q,)). The problem is that I get a TypeError
> (the Traceback at the end of this message). I don't know if this could
> be the cause or not but br is defined as the argmin of another function
> which I've defined (the code is currently pretty ugly but you can find
> it at http://pastebin.com/rEc6cKfd).
>
> Any help or suggestions will be much appreciated.
>
> Thanks,
> Ted To
>
> TypeError Traceback (most recent call last)
> /usr/lib/python2.7/dist-packages/IPython/utils/py3compat.pyc in
> execfile(fname, *where)
> 176 else:
> 177 filename = fname
> --> 178 __builtin__.execfile(filename, *where)
>
>
> /home/ted/texfiles/smoking/quality-computations/quality-provision-equilibrium.py
> in <module>()
> 66 return fixed_point(br,x0=p,args=(q,))
> 67
> ---> 68 print eqP(p,q)
> 69
> 70 def gstar(q):
>
>
> /home/ted/texfiles/smoking/quality-computations/quality-provision-equilibrium.py
> in eqP(p, q)
> 63
> 64 def eqP(p,q):
> ---> 65 print fixed_point(br,x0=p,args=(q,))
> 66 return fixed_point(br,x0=p,args=(q,))
> 67
>
> /usr/lib/python2.7/dist-packages/scipy/optimize/minpack.pyc in
> fixed_point(func, x0, args, xtol, maxiter)
> 509 p1 = func(p0, *args)
> 510 p2 = func(p1, *args)
> --> 511 d = p2 - 2.0 * p1 + p0
> 512 p = where(d == 0, p2, p0 - (p1 - p0)*(p1 - p0) / d)
> 513 relerr = where(p0 == 0, p, (p-p0)/p0)
>
> TypeError: can't multiply sequence by non-int of type 'float'
>
I suspect your function is returning a list in some cases. In the
multivariate case, the fixed_point function expects the return value of
your function to be a numpy array. Modify your code to ensure that br
always return a numpy array, and see if that fixes the problem. (One
option might be to pass in the parameters as arrays instead of lists. .e.g
fixed_point(br, x0=p, args=(array(q),)), but that depends on how br is
implemented.)
Warren
_______________________________________________
> SciPy-User mailing list
> SciPy-User@scipy.org
> http://mail.scipy.org/mailman/listinfo/scipy-user
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.scipy.org/pipermail/scipy-user/attachments/20120905/ad50a736/attachment-0001.html
More information about the SciPy-User
mailing list