sparse-matrix

问题 I\'m writing a machine learning algorithm on huge & sparse data (my matrix is of shape (347, 5 416 812 801) but very sparse, only 0.13% of the data is non zero. My sparse matrix\'s size is 105 000 bytes (<1Mbytes) and is of csr type. I\'m trying to separate train/test sets by choosing a list of examples indices for each. So I want to split my dataset in two using : training_set = matrix[train_indices] of shape (len(training_indices), 5 416 812 801) , still sparse testing_set = matrix[test

问题 I\'m working on a project, written in Java, which requires that I build a very large 2-D sparse array. Very sparse, if that makes a difference. Anyway: the most crucial aspect for this application is efficency in terms of time (assume loads of memory, though not nearly so unlimited as to allow me to use a standard 2-D array -- the key range is in the billions in both dimensions). Out of the kajillion cells in the array, there will be several hundred thousand cells which contain an object. I

问题 That is, if I use the current time as an index into the array: array[Date.getTime()] = value; will the interpreter instantiate all the elements from 0 to now? Do different browsers do it differently? I remember there used to be a bug in the AIX kernel, which would create pseudo-ttys on request, but if you did, say, \"echo > /dev/pty10000000000\" it would create /dev/pty0, /dev/pty1, .... and then fall over dead. It was fun at trade shows, but I don\'t want this to happen to my customers. 回答1: