关于numpy的使用

  1. np.dot与np.multiply
    前者是线代中的运算,后者是对应位置的元素相乘
  2. A trick when you want to flatten a matrix X of shape (a,b,c,d) to a matrix X_flatten of shape (b ∗ c ∗ d, a) is to use:
    X_flatten = X.reshape(X.shape[0], -1).T # X.T is the transpose of X