In [3]: type(mixfrac) Out[3]: <type 'list'> In [4]: mixfracarray=array(mixfrac)
In [5]: type(mixfracarray) Out[5]: <type 'numpy.ndarray'> (Is that what you were referring to?) On Fri, Mar 6, 2009 at 3:44 PM, Charles R Harris <charlesr.har...@gmail.com>wrote: > > > On Fri, Mar 6, 2009 at 3:36 PM, charles reid <charlesre...@gmail.com>wrote: > >> Hi there - >> >> I've imported some data from a file, and it's in a list called mixfrac. >> I'd like to take the Fourier transform of the data, but when I try to take >> the FFT of the list, I get this error: >> >> >> --------------------------------------------------------------------------- >> TypeError Traceback (most recent call >> last) >> >> /Users/charles/apriori/read.py in <module>() >> ----> 1 >> 2 >> 3 >> 4 >> 5 >> >> /Library/Python/2.5/site-packages/numpy-1.3.0.dev5825-py2.5-macosx-10.3-i386.egg/numpy/fft/fftpack.pyc >> in fft(a, n, axis) >> 105 """ >> 106 >> --> 107 return _raw_fft(a, n, axis, fftpack.cffti, fftpack.cfftf, >> _fft_cache) >> 108 >> 109 >> >> /Library/Python/2.5/site-packages/numpy-1.3.0.dev5825-py2.5-macosx-10.3-i386.egg/numpy/fft/fftpack.pyc >> in _raw_fft(a, n, axis, init_function, work_function, fft_cache) >> 64 if axis != -1: >> 65 a = swapaxes(a, axis, -1) >> ---> 66 r = work_function(a, wsave) >> 67 if axis != -1: >> 68 r = swapaxes(r, axis, -1) >> >> TypeError: array cannot be safely cast to required type >> >> >> so I convert to an array and run fft(mixfracarray). >> >> mixfracarray = array(mixfrac) >> fft(mixfracarray) >> >> whereupon I recieve the error >> >> >> --------------------------------------------------------------------------- >> TypeError Traceback (most recent call >> last) >> >> /Users/charles/apriori/read.py in <module>() >> ----> 1 >> 2 >> 3 >> 4 >> 5 >> >> /Library/Python/2.5/site-packages/numpy-1.3.0.dev5825-py2.5-macosx-10.3-i386.egg/numpy/fft/fftpack.pyc >> in fft(a, n, axis) >> 105 """ >> 106 >> --> 107 return _raw_fft(a, n, axis, fftpack.cffti, fftpack.cfftf, >> _fft_cache) >> 108 >> 109 >> >> /Library/Python/2.5/site-packages/numpy-1.3.0.dev5825-py2.5-macosx-10.3-i386.egg/numpy/fft/fftpack.pyc >> in _raw_fft(a, n, axis, init_function, work_function, fft_cache) >> 64 if axis != -1: >> 65 a = swapaxes(a, axis, -1) >> ---> 66 r = work_function(a, wsave) >> 67 if axis != -1: >> 68 r = swapaxes(r, axis, -1) >> >> TypeError: array cannot be safely cast to required type >> >> This is strange, because I can run fft(array([0,0,0,1,1,1])), or >> fft([0,0,0,1,1,1]), perfectly fine. This is passing an array and a list, >> respectively. >> >> type(mixfrac) is list and size(mixfrac) is 100; type(mixfracarray) is >> ndarray, and mixfracarray.shape is (100,). I've also tried taking the FFT >> of the transpose of mixfracarray, but that doesn't work either. >> >> I'm stumped - why can't I run an FFT on either mixfrac or mixfracarray? >> > > After you convert to an array what is the array type? I suspect an object > in there somewhere. > > Chuck > > > > _______________________________________________ > Numpy-discussion mailing list > Numpy-discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > >
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