diff options
Diffstat (limited to 'numpy/fft/fftpack.py')
| -rw-r--r-- | numpy/fft/fftpack.py | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/numpy/fft/fftpack.py b/numpy/fft/fftpack.py index 80d21ec1d..c70e336ea 100644 --- a/numpy/fft/fftpack.py +++ b/numpy/fft/fftpack.py @@ -271,7 +271,8 @@ def rfft(a, n=None, axis=-1): out : complex ndarray The truncated or zero-padded input, transformed along the axis indicated by `axis`, or the last one if `axis` is not specified. - The length of the transformed axis is ``n/2+1``. + If `n` is even, the length of the transformed axis is ``(n/2)+1``. + If `n` is odd, the length is ``(n+1)/2``. Raises ------ @@ -293,7 +294,7 @@ def rfft(a, n=None, axis=-1): conjugates of the corresponding positive-frequency terms, and the negative-frequency terms are therefore redundant. This function does not compute the negative frequency terms, and the length of the transformed - axis of the output is therefore ``n/2+1``. + axis of the output is therefore ``n//2+1``. When ``A = rfft(a)``, ``A[0]`` contains the zero-frequency term, which must be purely real due to the Hermite symmetry. @@ -343,7 +344,7 @@ def irfft(a, n=None, axis=-1): The input array. n : int, optional Length of the transformed axis of the output. - For `n` output points, ``n/2+1`` input points are necessary. If the + For `n` output points, ``n//2+1`` input points are necessary. If the input is longer than this, it is cropped. If it is shorter than this, it is padded with zeros. If `n` is not given, it is determined from the length of the input (along the axis specified by `axis`). |