Tranform Python code in Matlab

Question

Example Mo 2015-6-20

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/224668-tranform-python-code-in-matlab

评论： Example Mo 2015-6-21

Hello, I'm new to Matlab and I want to transform a simple python code.I tried to do that alone but I don't know how to make array indexation, in this case X[pairs[:,0],:] . Here is my code:

def learning_distance_symmetric(W,X,pairs,batch_size=10000):
 """Compute an array of Euclidean distances between points indexed by pairs
    To make it memory-efficient, we compute the array in several batches.
    Parameters
    ----------
    X : array, shape (n_samples, n_features)
        Data matrix
    W : array, shape (n_features,n_features)
        Learned distance matrix
    pairs : array, shape (n_pairs, 2)
        Pair indices
    batch_size : int
        Batch size (the smaller, the slower but less memory intensive)
    Output
    ------
    dist : array, shape (n_pairs,)
        The array of distances
    """
      n_pairs = pairs.shape[0]
      dist = np.ones((n_pairs,), dtype=np.dtype("float32"))
      for a in range(0, n_pairs, batch_size):
          b = min(a + batch_size, n_pairs)
          diff = X[pairs[:,0],:] - X[pairs[:,1],:]
          dist[a:b] = np.sum(np.dot(W,diff.T)*diff.T, axis=0)
      return dist