[SciPy-dev] Trouble with fmin_cg

[dmitrey]

I guess monitor(x0) is real number, not function.
Hence it yields error.
Maybe you need

fmin_cg(func,x0,callback=monitor) ?

BTW there is a way of connecting user-defined output func in openopt, I 
can explain you if you are interested (I haven't provided an example to 
OO documentation yet).

Regards, D.

Nils Wagner wrote:
> Hi all,
>
> If I run the following script
>
> from scipy import *
>
> def func(x):
>      return 0.5*dot(x,dot(A,x))-dot(x,b)
>
> def monitor(x):
>      res = linalg.norm(dot(A,x)-b)
>      return res
>
> n = 10
> x0 = zeros(n,float)
> A = random.rand(n,n)+diag(4*ones(n))
> A = 0.5*(A+A.T)
> b = random.rand(n)
>
> x = optimize.fmin_cg(func,x0,callback=monitor(x0))
>
> I get
>
> Traceback (most recent call last):
>    File "test_fmin_cg.py", line 16, in <module>
>      x = optimize.fmin_cg(func,x0,callback=monitor(x0))
>    File 
> "/usr/local/lib64/python2.5/site-packages/scipy/optimize/optimize.py", 
> line 911, in fmin_cg
>      callback(xk)
> TypeError: 'numpy.float64' object is not callable
>
> Is that a bug ?
>
> Nils
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