NIFTy2go, FFTOperator

Hi Martin,

unfortunately the FFTOperator on ProductSpaces does not work or am I missing something?

In [13]: x1 = ift.RGSpace(200)

In [14]: x2 = ift.RGSpace(200)

In [15]: k1 = x1.get_default_codomain()

In [16]: k2 = x2.get_default_codomain()

In [17]: FFT = ift.FFTOperator(domain=(x1,x2), target=(k1, k2), space=1)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-17-da937f755b58> in <module>()
----> 1 FFT = ift.FFTOperator(domain=(x1,x2), target=(k1, k2), space=1)

/Users/danielpumpe/CloudStation/dpumpe/construction/NIFTy_2go/lib/python2.7/site-packages/nifty2go-3.9.0-py2.7.egg/nifty2go/operators/fft_operator.pyc in __init__(self, domain, target, space)
     93         self._target = [dom for dom in self.domain]
     94         self._target[self._space] = target
---> 95         self._target = DomainTuple.make(self._target)
     96         adom.check_codomain(target)
     97         target.check_codomain(adom)

/Users/danielpumpe/CloudStation/dpumpe/construction/NIFTy_2go/lib/python2.7/site-packages/nifty2go-3.9.0-py2.7.egg/nifty2go/domain_tuple.pyc in make(domain)
     49         if isinstance(domain, DomainTuple):
     50             return domain
---> 51         domain = DomainTuple._parse_domain(domain)
     52         obj = DomainTuple._tupleCache.get(domain)
     53         if obj is not None:

/Users/danielpumpe/CloudStation/dpumpe/construction/NIFTy_2go/lib/python2.7/site-packages/nifty2go-3.9.0-py2.7.egg/nifty2go/domain_tuple.pyc in _parse_domain(domain)
     69             if not isinstance(d, DomainObject):
     70                 raise TypeError(
---> 71                     "Given object contains something that is not an "
     72                     "instance of DomainObject class.")
     73         return domain

TypeError: Given object contains something that is not an instance of DomainObject class.