Your problem is a very specific one. I don’t see how this will be of any use to anybody but yourself. There is no ‘one line solution’. There are many ways to approach indexing problems, I like to use scalar indexing when possible: Ncolumns = size(Matrix,1); Nblocks = floor(Ncolumns/4); %number of 4-line blocks (excluding the … Read more
I will try to guess what is asked. Assuming that your data frame is named df, you can convert each column to matrix and put it in list using lapply(). For example, I converted to matrix with two columns. seq_len(ncol(df) will make sequence of numbers from 1 to number of columns, so conversion will iterate … Read more
The question is a bit complicated and hard to follow.. Anyways I tried writing some code to the best of my understanding of the problem. Here is the part that finds the possible combinations: % input matrix A=[1 2 0 1 2 0 0 0 2 1 1 1 0 2 2 0 3 0 … Read more
You have the # lines as a separation between your matrix. So if you loop line by line on your file, you can separate the matrix with this # lines, and built them : file = open(“file.txt”, “r”) lines = file.readlines() At this point, lines is a list. lines[i] is the line n° i+1 as … Read more
I wanted to use my own implementation of the Strassen optimization for matrix multiplication. It is highly optimized and hence has almost no pedagogical use but then I remembered that Wikipedia has actual C code in the Strassen-matrix-multiplication entry. The implementation there is not the best: it has no fallback to the naive algorithm if … Read more
This is an algorithm which uses Lapace expansions, which recursively computes the determinant of an n x n matrix by computing n determinants of (n-1) x (n-1) subminors. The determinant of the 2 x 2 matrix should be obvious. There are better ways to do that, like LU decomposition. 1 solved Understanding of a specific … Read more
If you don’t know the external indice, you’d have to loop through every element in the array and compare the values of their x/y coordinates to your given coordinates, then return the ID when you find a match, or some sentinel value if you reach the end without finding a match. 0 solved Accesing 2d … Read more
If I understand correctly, you can generate all permutations of column indices with perms, and use the result to index into the matrix: M = magic(3); % // example matrix pp = perms(1:size(M,2)); % // each row is a permutation for p = pp.’ %’// “for” loops over columns, so transpose pp permuted_M = M(:,p); … Read more
If you could please point me towards some reading material that can teach me how to add, remove, get and iterate over the elements of the method suggested by you. Arrays don’t support those operations. To add and remove elements you really need to use a List such as ArrayList. List<List<Integer>> list2d = new ArrayList<>(); … Read more
First of all, in general, var <- expr evaluates the R expression expr and assigns the result to the variable var. If the statement occurs inside a function, then var becomes a function-local variable, otherwise, it becomes a global variable. c(0,0,0,1,0,1,0,1,1,1,1,0) Combines 12 double literals into a double vector in the order given. matrix(c(0,0,0,1,0,1,0,1,1,1,1,0),4,3, byrow=T … Read more