Re: [eigen] Problem with fft and custom allocator

[Marc Glisse <marc.glisse@xxxxxxxx>]

On Mon, 28 Mar 2016, Matthias Pospiech wrote:

> Am 27.03.2016 um 22:58 schrieb Matthias Pospiech:
> > Hello,
> > I am using the FFT of eigen, however with a custom allocator.
> > The custom one is based on the code from Nicolai M. Josuttis
> > http://www.josuttis.com/libbook/memory/myalloc.hpp.html
> > with fftw_malloc and fftw_free instead of new and delete.
> > The class is called fftalloc.
> >
> > This simple code however fails:
> > std::vector<complex<double>,fftalloc<complex<double>>>data(N); 
> > std::vector<complex<double>,fftalloc<complex<double>>>dataFourier(N); 
> > FFT<double>fft; fft.fwd(dataFourier,data);
> I solved it by defining a new set of functions:
>
>
> voidfwd(std::vector<Complex,fftalloc<Complex>>&dst,constvector<_Input,fftalloc<_Input>>&src)
> voidinv(std::vector<_Output,fftalloc<_Output>>&dst,conststd::vector<Complex,fftalloc<Complex>>&src,Indexnfft=-1)
>
> it compiles now and the result of ifft(fft(A)) differs now from A by << 1e-16
>
> The only restriction is now, that either non or both arrays must be defined 
> with or without the extra allocator.

I probably missed something obvious because I don't know that code, but 
from what you posted, I wonder why you are not making the allocator a 
template parameter:

template<typename _Input,class A1,class A2>
void fwd(std::vector<Complex,A1>&dst,const std::vector<_Input,A2>&src);


--
Marc Glisse