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吳恩達課後作業整合
https://blog.csdn.net/u013733326/article/details/79827273
問題集合
課程1_第3周_編程作業
(1)
# Visualize the data:
plt.scatter(X[0, :], X[1, :], c=Y, s=40, cmap=plt.cm.Spectral);
報錯:
ValueError: 'c' argument has 1 elements, which is not acceptable for use with 'x' with size 400, 'y' with size 400.
解決:
修改爲
plt.scatter(X[0, :], X[1, :], c=squeeze(Y), s=40, cmap=plt.cm.Spectral);
(2)
# Plot the decision boundary for logistic regression
plot_decision_boundary(lambda x: clf.predict(x), X, Y)
報錯: ValueError: RGBA sequence should have length 3 or 4 During handling of the above exception, another exception occurred:
……
ValueError: 'c' argument has 1 elements, which is not acceptable for use with 'x' with size 400, 'y' with size 400.
解決:
將 plt.scatter(X[0, :], X[1, :], c=y, cmap=plt.cm.Spectral)
修改爲 plt.scatter(X[0, :], X[1, :], c=squeeze(y), cmap=plt.cm.Spectral) 不起作用
將plot_decision_boundary函數中的:plot_decision_boundary(lambda x: clf.predict(x), X, Y)
修改爲 plot_decision_boundary(lambda x: clf.predict(x), X, Y.ravel()) 成功解決
原因:c 需要一維的array