Re: the performance of pycxx

[Barry S. <ba...@ba...>]

On 22 Nov 2011, at 03:39, <las...@si...> <las...@si...> wrote:

>     Py::Object fib (const Py::Tuple &args){
>         args.verify_length(1);
>         Py::Long res = args[0];
>         if (res<=Py::Long(1))  return Py::Long(1);
>         else{
>             Py::Tuple a(1), b(1); a[0]=Py::Long(res-2); b[0]=Py::Long(res-1);
>             return fib(a)+fib(b);
>         }
>     }


Following on from what Paul said:

Why use Python objects all the time if the goal is speed?

You have transliterated the pure Python code into C++
with all the costs that implies and none of Python's optimizations...
Of course its slow.

Do not use Py::Long when what you want for speed is int.

Create one function that computes the fib using pure C++.

Then have a second function that drives is from python.
That will avoid the costs of translating to and from the python
world.

Barry