matrix Questions
4
Solved
Assume I have the following matrix (defined here in Julia language):
mat = [1 1 0 0 0 ; 1 1 0 0 0 ; 0 0 0 0 1 ; 0 0 0 1 1]
Considering as a "component" a group of neighbour elements that have v...
6
Solved
I'm trying to make a function with the arguments (a,tol=1e-8) that returns a boolean value that tells the user whether or not the matrix is symmetric (symmetric matrix is equal to its transpose). S...
Mineralogy asked 20/3, 2017 at 15:59
11
I'm trying to make a simple matrix multiplication method using multidimensional arrays ([2][2]). I'm kinda new at this, and I just can't find what it is I'm doing wrong. I'd really appreciate any h...
Guillema asked 12/7, 2013 at 20:55
3
How can I find a permanent of a square matrix (for a general dimension nxn) in R? In particular, I'm trying to find a pdf of order statistics for independent but not identically distributed populat...
6
I'd like to take the modular inverse of a matrix like [[1,2],[3,4]] mod 7 in Python. I've looked at numpy (which does matrix inversion but not modular matrix inversion) and I saw a few number theor...
Fermium asked 26/11, 2010 at 18:28
4
I have a homogeneous transformation matrix of size (4x4) and a trajectory of size (nx3). Each row of this trajectory is a vector.
I want to multiply homogeneous transformation matrix by each row o...
35
Solved
A friend was in need of an algorithm that would let him loop through the elements of an NxM matrix (N and M are odd). I came up with a solution, but I wanted to see if my fellow SO'ers could come u...
2
Solved
I am trying to get the bird's eye view perspective transform from camera intrinsic, extrinsic matrices and distortion coefficients.
I tried using the answer from this question.
The image used is...
Radiancy asked 2/2, 2018 at 5:13
3
Solved
How can I squeeze only a subset of singleton dimensions of a matrix in Matlab? The squeeze function removes them all.
I keep the index to those dimensions in a vector called "dims".
Mossgrown asked 16/5, 2014 at 19:45
10
Solved
Given a 2D(M x N) matrix, and a 2D Kernel(K x L), how do i return a matrix that is the result of max or mean pooling using the given kernel over the image?
I'd like to use numpy if possible.
Note...
Febrifuge asked 26/2, 2017 at 0:6
10
Solved
How to identify the linearly independent rows from a matrix? For instance,
The 4th rows is independent.
Pyramid asked 2/3, 2015 at 18:12
1
Solved
Context
I've got a workflow with 2 jobs.
The first job generates a list of tasks (with name and type) as output
The second job uses 3 different actions, where each action is associated to a task t...
Battle asked 6/9, 2023 at 20:18
2
Solved
Suppose I have the following sudoku:
problem <- matrix(c(
5, 3, 0, 0, 7, 0, 0, 0, 0,
6, 0, 0, 1, 9, 5, 0, 0, 0,
0, 9, 8, 0, 0, 0, 0, 6, 0,
8, 0, 0, 0, 6, 0, 0, 0, 3,
4, 0, 0, 8, 0, 3, 0, 0,...
Aby asked 6/9, 2023 at 6:27
2
Solved
This code won't compile:
fn main() {
let m1 = vec![1, 2, 3];
let m2 = vec![&m1, &m1, &m1];
let m3 = vec![vec![1, 2, 3], vec![4, 5, 6], vec![7, 8, 9]];
for i in &m2 {
for j in...
8
I am trying to implement the Hungarian Algorithm but I am stuck on the step 5. Basically, given a n X n matrix of numbers, how can I find minimum number of vertical+horizontal lines such that the z...
Fifi asked 30/4, 2014 at 4:23
5
Solved
Given a vector I would like to create a square matrix where elements of vector are on diagonal and there is row-wise cumsum of elements.
Example vector:
vec <- c(1, 2, 3, 4)
Required output:...
5
Solved
Given two matrices
A: m * r
B: n * r
I want to generate another matrix C: m * n, with each entry C_ij being a matrix calculated by the outer product of A_i and B_j.
For example,
A: [[1, 2],
[...
3
Solved
I've got coordinates of 4 points in 2D that form a rectangle and their coordinates after a perspective transformation has been applied.
The perspective transformation is calculated in homogeneou...
Inca asked 5/3, 2016 at 19:58
3
Solved
I need help finding an Algorithm that is as effective as possible for checking if a given binary matrix can be reached by flipping rows and columns of a matrix with only one's.
Whenever you flip a ...
Inversion asked 27/2, 2018 at 12:11
2
Solved
I have a data frame with dimensions 3695 X 20. The first column contains alphanumeric identifiers, the other 19 columns are all numeric. So, rownames(df) provides the numbers 1-3695, and colnames(d...
3
I'm struggling with the following problem: I have some very big matrices (say, at least, 2000x2000, and probably in the future they will even reach 10000x10000) with very small rank (2 or 3, call i...
2
I am looking to use the multiprocessing module to speed up the run time of some Transport Planning models. I've optimized as much as I can via 'normal' methods but at the heart of it is an absurdly...
Lipscomb asked 3/11, 2011 at 0:50
5
Solved
Background
Assuming we have a family of matrices Ms of size n-by-n, which should meet the following requirements:
Entries of the matrix are either 0 or 1, i.e., boolean, but diagonal entries are a...
Skimmia asked 13/8, 2023 at 22:37
5
Solved
I'm having a numpy ndarray where I would like to check if each row vector is monotonically increasing.
Example:
a = np.asarray([[1,2,3],[1,5,7],[4,3,6]])
monotonically_increasing(a)
Expected re...
5
Solved
I am not sure if the approach I've been using in sympy to convert a MutableDenseMatrix to a numpy.array or numpy.matrix is a good current practice.
I have a symbolic matrix like:
g = sympy.Matrix...
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