Closed necronet closed 3 years ago
A minor point on reading about Discrete cosine transform chapter, there are two test function describe to build an M matrix (see bellow). The amp array is not used in any of them so it should be remove to avoid confusion.
Source: https://github.com/AllenDowney/ThinkDSP/blob/master/code/chap06.ipynb
def test1(): amps = np.array([0.6, 0.25, 0.1, 0.05]) N = 4.0 time_unit = 0.001 ts = np.arange(N) / N * time_unit max_freq = N / time_unit / 2 fs = np.arange(N) / N * max_freq args = np.outer(ts, fs) M = np.cos(PI2 * args) return M def test2(): amps = np.array([0.6, 0.25, 0.1, 0.05]) N = 4.0 ts = (0.5 + np.arange(N)) / N fs = (0.5 + np.arange(N)) / 2 args = np.outer(ts, fs) M = np.cos(PI2 * args) return M M = test2() M
Will fix. Thank you!
A minor point on reading about Discrete cosine transform chapter, there are two test function describe to build an M matrix (see bellow). The amp array is not used in any of them so it should be remove to avoid confusion.
Source: https://github.com/AllenDowney/ThinkDSP/blob/master/code/chap06.ipynb