![]() This may not be the approach actually used by Matlab, though. Putting these three facts together shows that it is possible to do it without a significant amount of extra memory. Transposition can be done inline, requiring only a fixed amount of extra memory, independent of array size, or growing very slowly with array size. Meshgrid-like function to generate 4D arrays in Matlab. Permute(., ) %// interchange dims 3 and 4: we have dims Įach of these elementary operations (interchanging two dimensions) is essentially a transpose along a given plane of the multidimensional array, performed repeatedly along all other dimensions. To illustrate, a three dimensional meshgrid seems to be equivalent to a three dimensional ngrid if the following permutations are done. Permute(., ) %// interchange dims 2 and 4: we have dims ![]() For example, permute(x, ) is equivalent to this sequence of elementary permute operations (the sequence is not unique): permute(., ) %// interchange dims 1 and 4: we have dims Permuting of dimensions can always be done as a sequence of elementary permute operations, where" elementary" means interchanging only two dimensions. B rot90 (A,k) rotates array A counterclockwise by k90 degrees, where k is an integer. For multidimensional arrays, rot90 rotates in the plane formed by the first and second dimensions. This is only a guess, as I don't really know what permute does under the hood. B rot90 (A) rotates array A counterclockwise by 90 degrees. While this is not exactly the best way to profile memory usage (better use a proper memory profiler, something like Intel Inspector XE), it does show to some degree that permute is indeed not working in-place. ![]() matrix whose i,jth element is (aij > 0.5). This allows the matrix to be modified, and doesn’t require a regular slice. You can see how at its peak the function reached twice as much memory usage as when it returned. access last element in MATLAB vector (1xn or nx1) or 1D NumPy array a (length n) The first through third rows and fifth through ninth columns of a 2D array, a. I also repeated the test under perfmon.exe which showed the same pattern: ![]() I then ran the function simply as: %clear aĪnd watched the memory usage It went from 1.8 gigs in use, and rose to 5.2 then quickly down to 3.6 gigs. I only have 8 gigs of RAM on my laptop, so to avoid thrashing I modified your function as: function out = mtest() I also set the "update speed" to "high" to get a finer time resolution. The ToMatlab-package is exactly what I need, but sadly it has some flaws, e.g. In Windows 10, I opened the "task manager" on the "performance" tab with the "memory" graphs in view. my question is a duplicate of : Is it possible to export the equations from Mathematica to MATLAB I did some symbolic calculations in Mathematica and want to transfer the result to Matlab. The permute method in fact does create a second copy of the matrix with the data permuted and returns it. Your argument is flawed because the MATLAB memory profiler is not telling you the truth! ![]()
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