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The sparse function in MATLAB does the following:

S = sparse(i,j,v) generates a sparse matrix S from the triplets i, j, and v such that S(i(k),j(k)) = v(k). The max(i)-by-max(j) output matrix has space allotted for length(v) nonzero elements. sparse adds together elements in v that have duplicate subscripts in i and j. If the inputs i, j, and v are vectors or matrices, they must have the same number of elements. Alternatively, the argument v and/or one of the arguments i or j can be scalars.

I would like to have a fairly equivalent function in Mathematica. Has anyone tried to do this beforehand?

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    $\begingroup$ Isn't SparseArray close enough? $\endgroup$ – Kuba May 26 '16 at 9:53
  • $\begingroup$ I'm not sure. What questions me is the different output of the Matlab function. $\endgroup$ – Mirko Aveta May 26 '16 at 10:35
  • $\begingroup$ The output in matlab. It's something different, perhaps because it is compressed. $\endgroup$ – Mirko Aveta May 26 '16 at 10:55
  • $\begingroup$ I think the difference lays in the compression of the memory. $\endgroup$ – Mirko Aveta May 26 '16 at 11:01
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    $\begingroup$ Then ask that question :) It is possible that there is someone around who knows both but this is MMA related site so you will gather more attention bringing info about Matlab side yourself. Moreover a motiviation would be good, e.g. specific example which Matlab handles way better than MMA and you want to know why. $\endgroup$ – Kuba May 26 '16 at 11:12
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Mathematica has sparse arrays not just sparse matrices:

Here are links to some tutorials:

The ability to use high-dimensional sparse array sometimes is very useful. (E.g. see "Markov chains n-gram model implementation".)

Most competitors of Mathematica support only sparse matrices.

Yifan Hu and Robert Knapp were the original designers of the functionality. I mention Yifan because before moving to Wolfram Research he worked with some of the originators and creators of the sparse matrices field (like John Reid).

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  • $\begingroup$ Slightly off-topic: if memory serves, wasn't the graph-plotting stuff an outgrowth of their work on sparse matrices? $\endgroup$ – J. M. will be back soon May 26 '16 at 12:29
  • $\begingroup$ @J.M. Yes, I would say so. Yifan designed and implemented GraphPlot and he was using it to demonstrate the origins of some of the matrices from Matrix Market. $\endgroup$ – Anton Antonov May 26 '16 at 12:41

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