43 lines
869 B
Markdown
43 lines
869 B
Markdown
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# PCA
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{:.no_toc}
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<nav markdown="1" class="toc-class">
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* TOC
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{:toc}
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</nav>
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## The goal
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Questions to [David Rotermund](mailto:davrot@uni-bremen.de)
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```python
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import numpy as np
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import matplotlib.pyplot as plt
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rng = np.random.default_rng(1)
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a_x = rng.normal(0.0, 1.0, size=(5000))[:, np.newaxis]
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a_y = rng.normal(0.0, 1.0, size=(5000))[:, np.newaxis] ** 3
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data_a = np.concatenate((a_x, a_y), axis=1)
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b_x = rng.normal(0.0, 1.0, size=(5000))[:, np.newaxis] ** 3
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b_y = rng.normal(0.0, 1.0, size=(5000))[:, np.newaxis]
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data_b = np.concatenate((b_x, b_y), axis=1)
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data = np.concatenate((data_a, data_b), axis=0)
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angle = -0.3
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roation_matrix = np.array(
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[[np.cos(angle), -np.sin(angle)], [np.sin(angle), np.cos(angle)]]
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)
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data_r = data @ roation_matrix
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plt.plot(data[:, 0], data[:, 1], "b.")
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plt.plot(data_r[:, 0], data_r[:, 1], "r.")
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```
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