Correction on Chapter 5 test functions
necronet opened this issue · 1 comments
necronet commented
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
AllenDowney commented
Will fix. Thank you!