Then I get the same array of matrices in lnA for both the MATLAB and R implementations. If I add lnA = cell(T, NumModalities) to the MATLAB script before your final for loop and then modify the inside of the loop to be lnA(outcomes(modal,tau),:,:,:,:,:),) Matrix P has the same data type as v, and it has n rows and n columns. MATLAB and Python may or may not make a copy of a tensor behind-the-scenes to improve performance. MATLAB uses inclusive ranges on indexing, while Python and MatX use exclusive ranges. Thus, permute (A, 2,1) flips dimension 2 (the columns) of array A with dimension 1 (the rows) of array A, which is equivalent to a transpose ( A' ). Each row of P contains a different permutation of the n elements in v. A row permutation has to send an entire row to the same row, so if they start on the same row, they end on the same row. MATLAB uses 1-based indexing while Python and MatX use 0-based indexing. permute does a permutation of the dimensions of an array, not of its elements, as one may expect from its name. Permute expr, gr returns the list of permuted forms of expr under the elements of the permutation group gr. Going back to the matrix A would entail multiplying again from the left by P 13: P 13 P 13 A ( P 13 P 13) A I A because every elementary permutation matrix (single transposition of rows) is its inverse: P P 1 or P 2 I. Permute expr, perm permutes the positions of the elements of expr according to the permutation perm. function I, PMat permutationFromTo (A,B) ,IA sort (A) ,IB sort (B) I (IB) IA PMat (:,I) eye (length (A)) You can use it via: A rand (10,1) B A (randperm (10)) I, PMat permutationFromTo (A,B) // All the following three lines will output the vector B. R does that by default unless you specify drop = FALSE when you subset an array, e.g., lnA] <- a],drop = FALSE] P perms(v) returns a matrix containing all permutations of the elements of vector v in reverse lexicographic order. The permutation matrix is applied to the left. In the MATLAB script, permute appears to be simply dropping excess dimensions. I don't think you actually need an equivalent for permute. P.s: Edit tags as appropriate, I added as many as made sense to me.I believe I successfully replicated the MATLAB script in R. I know about permutation matrices, but they only permute entire rows and columns not individual entries.įor example: Say I want to permute $x_ MATLAB provides the following functions to sort, rotate, permute. I want to permute two entries in $A$, any two entries as needed: In general, for any two entries $a_j,b_k$ in the matrix is it possible to do this with some matrix $B$ dependent on $a_j,b_k$? You can do this in one line using the functions NUM2CELL to break the matrix X into a cell array and CELLFUN to operate across the cells: Z cellfun ( (x) xY,num2cell (X, 1 2),UniformOutput,false) The result Z is a 1-by-C cell array where each cell contains an A-by-D matrix. MATLAB Arrays - All variables of all data types in MATLAB are multidimensional arrays. Let $A$ be an $8 \times 8$ matrix with integer coefficients. Use the Permute Matrix block to permute a matrix by row or column.
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