Compute the one-dimensional inverse discrete Fourier Transform. This function computes the inverse of the one-dimensional *n*-point discrete Fourier transform computed by `fft`. In other words, ``ifft(fft(a)) == a`` to within numerical accuracy. For a general description of th
(a, n=None, axis=-1, norm=None, out=None)
| 218 | |
| 219 | @array_function_dispatch(_fft_dispatcher) |
| 220 | def ifft(a, n=None, axis=-1, norm=None, out=None): |
| 221 | """ |
| 222 | Compute the one-dimensional inverse discrete Fourier Transform. |
| 223 | |
| 224 | This function computes the inverse of the one-dimensional *n*-point |
| 225 | discrete Fourier transform computed by `fft`. In other words, |
| 226 | ``ifft(fft(a)) == a`` to within numerical accuracy. |
| 227 | For a general description of the algorithm and definitions, |
| 228 | see `numpy.fft`. |
| 229 | |
| 230 | The input should be ordered in the same way as is returned by `fft`, |
| 231 | i.e., |
| 232 | |
| 233 | * ``a[0]`` should contain the zero frequency term, |
| 234 | * ``a[1:n//2]`` should contain the positive-frequency terms, |
| 235 | * ``a[n//2 + 1:]`` should contain the negative-frequency terms, in |
| 236 | increasing order starting from the most negative frequency. |
| 237 | |
| 238 | For an even number of input points, ``A[n//2]`` represents the sum of |
| 239 | the values at the positive and negative Nyquist frequencies, as the two |
| 240 | are aliased together. See `numpy.fft` for details. |
| 241 | |
| 242 | Parameters |
| 243 | ---------- |
| 244 | a : array_like |
| 245 | Input array, can be complex. |
| 246 | n : int, optional |
| 247 | Length of the transformed axis of the output. |
| 248 | If `n` is smaller than the length of the input, the input is cropped. |
| 249 | If it is larger, the input is padded with zeros. If `n` is not given, |
| 250 | the length of the input along the axis specified by `axis` is used. |
| 251 | See notes about padding issues. |
| 252 | axis : int, optional |
| 253 | Axis over which to compute the inverse DFT. If not given, the last |
| 254 | axis is used. |
| 255 | norm : {"backward", "ortho", "forward"}, optional |
| 256 | Normalization mode (see `numpy.fft`). Default is "backward". |
| 257 | Indicates which direction of the forward/backward pair of transforms |
| 258 | is scaled and with what normalization factor. |
| 259 | |
| 260 | .. versionadded:: 1.20.0 |
| 261 | |
| 262 | The "backward", "forward" values were added. |
| 263 | |
| 264 | out : complex ndarray, optional |
| 265 | If provided, the result will be placed in this array. It should be |
| 266 | of the appropriate shape and dtype. |
| 267 | |
| 268 | .. versionadded:: 2.0.0 |
| 269 | |
| 270 | Returns |
| 271 | ------- |
| 272 | out : complex ndarray |
| 273 | The truncated or zero-padded input, transformed along the axis |
| 274 | indicated by `axis`, or the last one if `axis` is not specified. |
| 275 | |
| 276 | Raises |
| 277 | ------ |
searching dependent graphs…