Hello, Being new to R, I am completely stuck with the following problem. Please help to find a general solution to the following matrix task: Given:
N<-4 input_mat<-matrix(c(1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0),ncol=N) combin_mat<-matrix(c(1, 2, 1, 3, 1, 4, 2, 3, 2, 4, 3, 4),ncol=choose(N,2)) Find the indices of rows in "input_mat", whose elements indicated by the pair of elements in each column of "combin_mat", are equal 1. So, for the first column of combin_mat (1,2) the answer should be 1,2,3, and 4th row of "input_mat" has 1 as the first and second element, for the secondcolumn of combin_mat (1,3) the answer should be 1,2,5,6, for the third column of combin_mat (1,4) the answer should be 1,3,5,7, an so on. "input_mat" is the matrix of binary representations of the first 2^N-1 decimals in the descending order, here N=4, so 7,6,...,0. "combin_mat" is the matrix of all combinations of N by 2. ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html