Hot-keys on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
r""" Discrete Fourier Transforms
This file contains functions useful for computing discrete Fourier transforms and probability distribution functions for discrete random variables for sequences of elements of `\QQ` or `\CC`, indexed by a ``range(N)``, `\ZZ / N \ZZ`, an abelian group, the conjugacy classes of a permutation group, or the conjugacy classes of a matrix group.
This file implements:
- :meth:`__eq__`
- :meth:`__mul__` (for right multiplication by a scalar)
- plotting, printing -- :meth:`IndexedSequence.plot`, :meth:`IndexedSequence.plot_histogram`, :meth:`_repr_`, :meth:`__str__`
- dft -- computes the discrete Fourier transform for the following cases:
* a sequence (over `\QQ` or :class:`CyclotomicField`) indexed by ``range(N)`` or `\ZZ / N \ZZ` * a sequence (as above) indexed by a finite abelian group * a sequence (as above) indexed by a complete set of representatives of the conjugacy classes of a finite permutation group * a sequence (as above) indexed by a complete set of representatives of the conjugacy classes of a finite matrix group
- idft -- computes the discrete Fourier transform for the following cases:
* a sequence (over `\QQ` or CyclotomicField) indexed by ``range(N)`` or `\ZZ / N \ZZ`
- dct, dst (for discrete Fourier/Cosine/Sine transform)
- convolution (in :meth:`IndexedSequence.convolution` and :meth:`IndexedSequence.convolution_periodic`)
- fft, ifft -- (fast Fourier transforms) wrapping GSL's ``gsl_fft_complex_forward()``, ``gsl_fft_complex_inverse()``, using William Stein's :func:`FastFourierTransform`
- dwt, idwt -- (fast wavelet transforms) wrapping GSL's ``gsl_dwt_forward()``, ``gsl_dwt_backward()`` using Joshua Kantor's :func:`WaveletTransform` class. Allows for wavelets of type:
* "haar" * "daubechies" * "daubechies_centered" * "haar_centered" * "bspline" * "bspline_centered"
.. TODO::
- "filtered" DFTs - more idfts - more examples for probability, stats, theory of FTs
AUTHORS:
- David Joyner (2006-10)
- William Stein (2006-11) -- fix many bugs """
########################################################################## # Copyright (C) 2006 David Joyner <wdjoyner@gmail.com> # # Distributed under the terms of the GNU General Public License (GPL): # # http://www.gnu.org/licenses/ ##########################################################################
from sage.misc.superseded import deprecation deprecation(9084, "the module sage.gsl.dft has moved to sage.calculus.transforms.dft")
from sage.calculus.transforms.dft import * |