summaryrefslogtreecommitdiff
path: root/numpy/dft/helper.py
diff options
context:
space:
mode:
authorTravis Oliphant <oliphant@enthought.com>2006-08-04 23:32:12 +0000
committerTravis Oliphant <oliphant@enthought.com>2006-08-04 23:32:12 +0000
commitf1cca04886d4f63f7b1ed5b382986af3a9ee6a61 (patch)
tree053f566b31cb6edc24a41b800ec7f2972c4bca40 /numpy/dft/helper.py
parent8f26568de7cc97ac0dcedfd5061e08bb54770b61 (diff)
downloadnumpy-f1cca04886d4f63f7b1ed5b382986af3a9ee6a61.tar.gz
Many name-changes in oldnumeric. This may break some numpy code that was using the oldnumeric interface.
Diffstat (limited to 'numpy/dft/helper.py')
-rw-r--r--numpy/dft/helper.py66
1 files changed, 0 insertions, 66 deletions
diff --git a/numpy/dft/helper.py b/numpy/dft/helper.py
deleted file mode 100644
index 4e1da2abd..000000000
--- a/numpy/dft/helper.py
+++ /dev/null
@@ -1,66 +0,0 @@
-"""
-Discrete Fourier Transforms - helper.py
-"""
-# Created by Pearu Peterson, September 2002
-
-__all__ = ['fftshift','ifftshift','fftfreq']
-
-from numpy.core import asarray, concatenate, arange, take, \
- array, integer
-import types
-
-def fftshift(x,axes=None):
- """ fftshift(x, axes=None) -> y
-
- Shift zero-frequency component to center of spectrum.
-
- This function swaps half-spaces for all axes listed (defaults to all).
-
- Notes:
- If len(x) is even then the Nyquist component is y[0].
- """
- tmp = asarray(x)
- ndim = len(tmp.shape)
- if axes is None:
- axes = range(ndim)
- y = tmp
- for k in axes:
- n = tmp.shape[k]
- p2 = (n+1)/2
- mylist = concatenate((arange(p2,n),arange(p2)))
- y = take(y,mylist,k)
- return y
-
-
-def ifftshift(x,axes=None):
- """ ifftshift(x,axes=None) - > y
-
- Inverse of fftshift.
- """
- tmp = asarray(x)
- ndim = len(tmp.shape)
- if axes is None:
- axes = range(ndim)
- y = tmp
- for k in axes:
- n = tmp.shape[k]
- p2 = n-(n+1)/2
- mylist = concatenate((arange(p2,n),arange(p2)))
- y = take(y,mylist,k)
- return y
-
-def fftfreq(n,d=1.0):
- """ fftfreq(n, d=1.0) -> f
-
- DFT sample frequencies
-
- The returned float array contains the frequency bins in
- cycles/unit (with zero at the start) given a window length n and a
- sample spacing d:
-
- f = [0,1,...,n/2-1,-n/2,...,-1]/(d*n) if n is even
- f = [0,1,...,(n-1)/2,-(n-1)/2,...,-1]/(d*n) if n is odd
- """
- assert isinstance(n,types.IntType) or isinstance(n, integer)
- k = range(0,(n-1)/2+1)+range(-(n/2),0)
- return array(k,'d')/(n*d)