![]() ![]() Yes, this looks hard and it is indeed hard! To check if you understand thoroughly, try predicting a square Matrix's similar different permutations. So, there will be 1 4x2 (4x2x1) matrix(itself!). * G = permute(A,) % this makes no difference, using to show the reasoningĤx2x1 ( row(1) dimension of A = 4, column(2) dimension of A = 2, page(3) dimension of A = 1 4 is row dimension, 2 is column dimension and 1 is page dimension for the generated G) * F = permute(A,) % this is transpose and same as Ģx4x1 ( column(2) dimension of A = 2, row(1) dimension of A = 4, page(3) dimension of A = 1 2 is row dimension, 4 is column dimension and 1 is page dimension for the generated F) So, there will be 4 2x1 (2x1x4) column matrixes. As in: ans(:,:,1) =Ģx1x4 ( column(2) dimension of A = 2, page(3) dimension of A = 1, row(1) dimension of A = 4 2 is row dimension, 1 is column dimension and 4 is page dimension for the generated E) So, there will be 2 4x1 (4x1x2) column matrixes. As in: ans(:,:,1) =Ĥx1x2 ( row(1) dimension of A = 4, page(3) dimension of A = 1, column(2) dimension of A = 2 4 is row dimension, 1 is column dimension and 2 is page dimension for the generated D) So, there will be 2 1x4 (1x4x2) row matrixes. As in: ans(:,:,1) =ġx4x2 ( page(3) dimension of A = 1, row(1) dimension of A = 4, column(2) dimension of A = 2 1 is row dimension, 4 is column dimension and 2 is page dimension for the generated C) So, there will be 4 1x2 (1x2x4) row matrixes. G = permute(A,) % means ġx2x4 ( page(3) dimension of A = 1, column(2) dimension of A = 2, row(1) dimension of A = 4 1 is row dimension, 2 is column dimension and 4 is page dimension for the generated B. % 3 = page, 2 = column and 1 = row dimensions):ī = permute(A,) % means Ĭ = permute(A,) % means ĭ = permute(A,) % means Į = permute(A,) % means į = permute(A,) % means % (numbers in the order argument of permute function indicates dimensions, Now let's move to the examples, Finally: % A has 4 rows, 2 columns and 1 page Order argument passed to permute swap these dimensions in the matrix and produce an awkward combination of arrays, I think permute is a misnomer for this effect. B=zeros(10,3) has 10 rows, 3 columns and 1 page, this order is important!) And if you don't specify a dimension, its default count is set to 1. Here are some examples to prevent you from suffering a similar excruciating pain:įirst, let's remember the dimensions' names of matrix in matlab: A = zeros(4,5,7), matrix A has 4 rows, 5 columns and 7 pages. Therefore, I used the F*ck word many times during " my journey of understanding the permute function". In particular, since permutation matrices are orthogonal matrices with nonnegative elements, we define two gradient flows in the space of orthogonal matrices.Wow, this is one of the hardest functions to figure out among all the different SDKs I have used up to now. "A dynamical systems approach to weighted graph matching". Most authors choose one representation to be consistent with other notation they have introduced, so there is generally no need to supply a name. n-queens puzzle, a permutation matrix in which there is at most one entry in each diagonal and antidiagonal.Costas array, a permutation matrix in which the displacement vectors between the entries are all distinct.So, permutation matrices do indeed permute the order of elements in vectors multiplied with them. Each such matrix, say P, represents a permutation of m elements and, when used to multiply another matrix, say A, results in permuting the rows (when pre-multiplying, to form PA) or columns (when post-multiplying, to form AP) of the matrix A. In mathematics, particularly in matrix theory, a permutation matrix is a square binary matrix that has exactly one entry of 1 in each row and each column and 0s elsewhere. ( August 2022) ( Learn how and when to remove this template message) Please help to improve this article by introducing more precise citations. So then you can use: idx randperm (numel (A),2) A. In recent versions of matlab randperm takes two arguments: p randperm (n,k) returns a row vector containing k unique integers selected randomly from 1 to n inclusive. No need to permute, just pick two random indexes. This article includes a list of general references, but it lacks sufficient corresponding inline citations. So basically, you just want to add 2 to 2 random elements of the vector A. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |