diff options
Diffstat (limited to 'numpy/fft/fftpack.py')
| -rw-r--r-- | numpy/fft/fftpack.py | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/numpy/fft/fftpack.py b/numpy/fft/fftpack.py index 1cb24f2b7..fb7c19dd5 100644 --- a/numpy/fft/fftpack.py +++ b/numpy/fft/fftpack.py @@ -68,10 +68,10 @@ def _raw_fft(a, n=None, axis=-1, init_function=fftpack.cffti, def fft(a, n=None, axis=-1): """fft(a, n=None, axis=-1) - Will return the n point discrete Fourier transform of a. n defaults to the - length of a. If n is larger than a, then a will be zero-padded to make up - the difference. If n is smaller than a, the first n items in a will be - used. + Return the n point discrete Fourier transform of a. n defaults to + the length of a. If n is larger than the length of a, then a will + be zero-padded to make up the difference. If n is smaller than + the length of a, only the first n items in a will be used. The packing of the result is "standard": If A = fft(a, n), then A[0] contains the zero-frequency term, A[1:n/2+1] contains the @@ -90,10 +90,11 @@ def fft(a, n=None, axis=-1): def ifft(a, n=None, axis=-1): """ifft(a, n=None, axis=-1) - Will return the n point inverse discrete Fourier transform of a. n - defaults to the length of a. If n is larger than a, then a will be - zero-padded to make up the difference. If n is smaller than a, then a will - be truncated to reduce its size. + Return the n point inverse discrete Fourier transform of a. n + defaults to the length of a. If n is larger than the length of a, + then a will be zero-padded to make up the difference. If n is + smaller than the length of a, then a will be truncated to reduce + its size. The input array is expected to be packed the same way as the output of fft, as discussed in it's documentation. @@ -115,9 +116,9 @@ def ifft(a, n=None, axis=-1): def rfft(a, n=None, axis=-1): """rfft(a, n=None, axis=-1) - Will return the n point discrete Fourier transform of the real valued - array a. n defaults to the length of a. n is the length of the input, not - the output. + Return the n point discrete Fourier transform of the real valued + array a. n defaults to the length of a. n is the length of the + input, not the output. The returned array will be the nonnegative frequency terms of the Hermite-symmetric, complex transform of the real array. So for an 8-point @@ -136,11 +137,11 @@ def rfft(a, n=None, axis=-1): def irfft(a, n=None, axis=-1): """irfft(a, n=None, axis=-1) - Will return the real valued n point inverse discrete Fourier transform of - a, where a contains the nonnegative frequency terms of a Hermite-symmetric - sequence. n is the length of the result, not the input. If n is not - supplied, the default is 2*(len(a)-1). If you want the length of the - result to be odd, you have to say so. + Return the real valued n point inverse discrete Fourier transform + of a, where a contains the nonnegative frequency terms of a + Hermite-symmetric sequence. n is the length of the result, not the + input. If n is not supplied, the default is 2*(len(a)-1). If you + want the length of the result to be odd, you have to say so. If you specify an n such that a must be zero-padded or truncated, the extra/removed values will be added/removed at high frequencies. One can |