On Thu, Oct 16, 2008 at 07:12:11PM +0200, Ondrej Certik wrote:
> Hi,
>
> I want to use scipy's quadrature like this:
>
> val, err = quadrature(func2, a, b, args=(f,))
>
> where func2 is my Cython function and "f" is a C function pointer,
> that will get executed from func2. The problem is, that "f" is passed
> to the Python quadrature function, so it needs to be wrapped.
> Currently what I do is:
>
>
> cdef class MyFunc:
> cdef f2 thisptr
>
> cdef set_f(MyFunc self, f2 f):
> self.thisptr = f
>
> cdef f2 get_f(MyFunc self):
> return self.thisptr
>
>
> cdef MyFunc mf = MyFunc()
> mf.set_f(f)
> val, err = quadrature(func2, a, b, args=(mf,))
>
> Where func2 is:
>
> def func2(a, MyFunc mf):
> cdef f2 f = mf.get_f()
> return array([f(x) for x in a])
>
> This works nice. Is this the way to do it? Or is there some
> better/simpler way. I don't know if it's a good idea to make Cython
> clever enough to wrap things like this automatically?
>
I often just use a closure (I assume your are doing this all in cython), so
you can just have:
cdef double f(double x):
return x*x
def func2(a):
return array([f(x) for x in a])
val, err = quadrature(func2, a, b)
Though I am not sure if this works in your case. When we come to a consensus on
the idiomatic way of doing this we should write up some documentation!
Gabriel
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