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March 31, 2020 09:19
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Rotation of 2d DFT coefficients, avoiding computing a DFT by directly transforming the DFT coefficients
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| import numpy | |
| def rot180_fft_2d(X, N): | |
| I = numpy.repeat([numpy.arange(N)], N, axis = 0) | |
| K = numpy.exp((2 * numpy.pi / N) * (I + I.T) * 1j) | |
| return K * numpy.conj(X) | |
| def rot180_rfft_2d(X, N): | |
| I = numpy.repeat([numpy.arange(N)], N, axis = 0) | |
| K = numpy.exp((2 * numpy.pi / N) * (I + I.T) * 1j)[:,:N // 2 + 1] | |
| return K * numpy.conj(X) |
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