matrix

问题 I have a matrix like the following: ` matrix = [ ['P', 'o', 'P', 'o', 'P'], ['m', 'i', 'c', 's', 'r'], ['g', 'a', 'T', 'A', 'C'], ['n', 'n', 'e', 'r', 't'], ['a', 'g', 'o', 'd', 'o'], ['a', 'p', 'p', 'l', 'e'] ]` and this code which prints every letter in a 'diagonal rising to the right' way with repetitions: `test_word = '' for upper in range(len(matrix)): for rep1 in range(min(upper + 1, len(matrix[0]))): for rep2 in range(rep1, min(upper + 1, len(matrix[0]))): for j in range(rep1, rep2 + 1

问题 I have a matrix like the following: ` matrix = [ ['P', 'o', 'P', 'o', 'P'], ['m', 'i', 'c', 's', 'r'], ['g', 'a', 'T', 'A', 'C'], ['n', 'n', 'e', 'r', 't'], ['a', 'g', 'o', 'd', 'o'], ['a', 'p', 'p', 'l', 'e'] ]` and this code which prints every letter in a 'diagonal rising to the right' way with repetitions: `test_word = '' for upper in range(len(matrix)): for rep1 in range(min(upper + 1, len(matrix[0]))): for rep2 in range(rep1, min(upper + 1, len(matrix[0]))): for j in range(rep1, rep2 + 1

问题 Suppose you have one matrix of height h and width w (h,w <= 500) You have to find two submatrices of same size that are equal. Any idea for solving ? 回答1: You can enumerate all vectors (-h < dh < h, 0 <= dw < w) in O(hw) . For each such vector, translate the matrix by the vector (dh, dw) and subtract the translated matrix from the original one. In the range where they overlap you want to find the rectangle of zeroes that has the largest area. You can use a linear time algorithm to do that.

问题 I have a multi dimensional array in julia: julia> ac.value 3x100x3 Array{Float64,3}: [:, :, 1] = 0.29238 0.0751815 0.00843636 … -0.0143826 0.0403283 0.0225896 0.263146 0.080687 0.000462262 -0.00635778 0.0307563 0.0379104 0.992458 0.986423 0.980587 0.561173 0.55516 0.549105 [:, :, 2] = 0.362155 0.13406 0.0741124 … 0.0231614 0.0156455 0.0121797 0.325581 0.11181 0.0447847 0.0098042 0.0193873 0.0146943 0.914888 0.852297 0.796608 -0.0500265 -0.0551787 -0.0520171 [:, :, 3] = 0.269976 0.108082 0

问题 If I have constructed a sparse matrix using the sparse(i, j, k) constructor, how can I then normalize the columns of the matrix (so that each column sums to 1)? I cannot efficiently normalize the entries before I create the matrix, so any help is appreciated. Thanks! 回答1: The easiest way would be a broadcasting division by the sum of the columns: julia> A = sprand(4,5,.5) A./sum(A,1) 4x5 Array{Float64,2}: 0.0 0.0989976 0.0 0.0 0.0795486 0.420754 0.458653 0.0986313 0.0 0.0 0.0785525 0.442349 0

问题 This question already has answers here : Creating a symmetric matrix in R (4 answers) Make a matrix symmetric (1 answer) Closed 4 years ago . I have a lower triangular of a matrix that I'm trying to convert to a dissim matrix and thus it needs to be symmetric. print(rdf) X0 X1 X2 X3 X4 0 0.0000000 NA NA NA NA 1 0.5340909 0.0000000 NA NA NA 2 0.5340909 0.0000000 0.0000000 NA NA 3 0.3200000 0.5227273 0.5227273 0.0000000 NA 4 0.6263736 0.4945055 0.4945055 0.5384615 0 library(gdata) upperTriangle

问题 I am trying to create a set of rolling covariance matrices on financial data (window size = 60). Returns is a 125x3 df. import pandas as pd roll_rets = returns.rolling(window=60) Omega = roll_rets.cov() Omega is a 375x3 data frame with what looks like a multi-index - i.e. there are 3 values for each timestamp. What I actually want this to return is a set of 66 3x3 covariance matrices (i.e. one for each period), but I can't work out how to iterate over returns correctly to do this. I think I'm

问题 New to Matlab come from C/C++...... I have an array of objects and I'm trying to access the values of every single object in the array and concatenate them into one variable. Class sample properties(GetAccess = 'public', SetAccess ='public') ID; Value; end methods function obj = sample(id, value) obj.ID = id; obj.Value = value; end end end Then I make an matrix containing some of the objects. x = sample.empty(3,0); x(1) = sample(1,3); x(2) = sample(1,4); x(3) = sample(1,5); Then I want to get

问题 I need to loop through the diagonal+1 (i.e. the values 1 column to the right of the diagonal) and write the value to a column in a dataframe: write.csv(data.frame(matrix[1,2], matrix[2,3], matrix[3,4]) How can I do this using a function, rather than just listing all the positions of the values? 回答1: You can index using a matrix. eg m <- matrix(1:25, ncol = 5) The off diagonals can be accessed using offd <- cbind(1:4,2:5) m[offd] ## [1] 6 12 18 24 You could create a function that does this

问题 Following Jama Matrices are defined in my code: P: 3*3 Matrix I: 3*3 identity Matrix K: 3*2 Matrix H: 2*3 Matrix Q: 3*3 Matrix Following is my code snippet: private Matrix getP() { P= (I.minus(K.times(H))).times(Q); Log.d("csv", "P is calculated"); return P; } While running the code, at first iteration it works, i.e, P is calculated is printed at the Logcat. However, it happens only once and the application gets stopped. Following is the error: java.lang.IllegalArgumentException: Matrix inner