12/17/2022 0 Comments Permute rows of a matrixI've used a different example array in this case - your version will yield an identical output after performing the row/column swaps which makes it difficult to understand what's going on. Permutations are invertible, so if they cant take two elements on the same row to different rows, they cant take elements on different rows to the same row. 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. You can use the same indexing approach to swap columns. A column permutation wont affect what row anything is on. In this particular case you could avoid the copy by using slice indexing, which returns a view rather than a copy: b = b # invert the row order Note that array indexing always returns a copy rather than a view - there's no way to swap arbitrary rows/columns of an array without generating a copy. When the Permute parameter is set to Rows, the. Python indexing starts at 0 rather than 1) The Permute Matrix block reorders the rows or columns of M-by-N input matrix A as specified by indexing input P. You can perform the swap in a one-liner using integer array indexing: a = np.array(, EXERCISE 3 If you havent already done so, enter the. Furthermore, I need to do an arbitrary number of permutations (more than one). One way to construct permutation matrices is to permute the rows (or columns) of the identity matrix. I'm following some projects ideas from the book 'Exploring Linear Algebra in Mathematica', here it says that PermutationsName of the Matrix should do the work, but I cannot get to use it that way. That doesn't work for me because the matrices are adjacency matrices (representing graphs), and I need to do the permutations which will give me a graph which is isomorphic with the original graph. Hi I've been having some touble with trying to find a function that lets me permute the row of a matrix. numpy.shuffle and numpy.permutation seem to permute only the rows of the matrix (not the columns at the same time). Now, an incredibly naive (and memory costly) way of doing so might be: a2 = deepcopy(a1)īut, I would like to know if there is something more efficient that does this. Assuming that I have the following matrix/array: array(,Īnd I want to apply the following permutation: 1 -> 5
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