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from training accuracy.\nheld=np.random.default_rng(107).normal(size=(256,4));held_y=held@true>0\nprint('same-rule held-out accuracy:',float(((held@w>0)==held_y).mean()))\nshuffled=np.random.default_rng(17).permutation(y);ws=np.zeros(4)\nfor step in range(200):\n    ps=1/(1+np.exp(-X@ws));ws-=.2*(X.T@(ps-shuffled))/len(shuffled)\nprint('only training labels shuffled, held-out true-rule accuracy:',float(((held@ws>0)==held_y).mean()))\n```","sha256":"4b2db02d51801a2a049f21dd444b05dd5995a8f2d564735ec14e1a2a5ab275c7","chapter":{"id":"course","title":"选读热身：四维分类的参数更新 · 实现代码"},"unit":{"id":"notebook-blocks/bec8290eec6f4d2099698e2e9a5971f7","title":"选读热身：四维分类的参数更新 · 实现代码"},"page":{"id":"reading-opening","title":"选读热身：四维分类的参数更新 · 实现代码","number":1},"sectionTitle":"选读热身：四维分类的参数更新 · 实现代码","currentQuestion":"选读热身：四维分类的参数更新 · 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