Hi Rafael,
On Sun, Jul 26, 2009 at 6:29 AM, Rafael Costa<rfc...@gmail.com> wrote:
>
> Why Sage not execute the python code?
>
> from scipy import *
> from pylab import *
>
> sample_rate=1000.00
> t=r_[0:0.6:1/sample_rate]
> N=len(t)
> s=sin(2*pi*50*t)+sin(2*pi*70*t+pi/4)
> S=fft(s)
> f=sample_rate*r_[0:(N/2)]/N
> n=len(f)
> plot(f,abs(S[0:n])/N)
Well, I get this far:
----------------------------------------------------------------------
| Sage Version 4.1, Release Date: 2009-07-09 |
| Type notebook() for the GUI, and license() for information. |
----------------------------------------------------------------------
sage: from scipy import *
sage: from pylab import *
sage: sample_rate = 1000.0
sage: t = r_[0:0.6:1/sample_rate]
sage: N = len(t)
sage: s = [sin(2*pi*50*elem) + sin(2*pi*70*elem + (pi/4)) for elem in t]
sage: S = fft(s)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/home/mvngu/.sage/temp/sage.math.washington.edu/6349/_home_mvngu__sage_init_sage_0.py
in <module>()
/usr/local/sage/local/lib/python2.6/site-packages/numpy/fft/fftpack.pyc
in fft(a, n, axis)
157 """
158
--> 159 return _raw_fft(a, n, axis, fftpack.cffti, fftpack.cfftf,
_fft_cache)
160
161
/usr/local/sage/local/lib/python2.6/site-packages/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
The problem is that Sage and NumPy do not yet talk to each other very
well. The relevant tickets to accomplish this are:
#6497
http://trac.sagemath.org/sage_trac/ticket/6497
#5081
http://trac.sagemath.org/sage_trac/ticket/5081
#6506
http://trac.sagemath.org/sage_trac/ticket/6506
--
Regards
Minh Van Nguyen
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