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1 vote
2 answers
137 views

Methods to solve for a matrix whose entries satisfy certain properties

(This question is a repost of a deleted question I asked, because the previous version had several elements missing) Setting For fixed $N \in \mathbb{N}$, I wish to compute the entries of a matrix $...
algebroo's user avatar
  • 135
2 votes
0 answers
149 views

Random sparse and invertible matrices

Let $n\leq m$ and $0\leq k\leq (n\times m - \min\{n,m\})$ be in $\mathbb{N}$. Let $\mu$ be a probability measure dominated by the Lebesgue measure on $\mathbb{R}$ and generate a random $n\times m$ ...
ABIM's user avatar
  • 5,405
5 votes
1 answer
839 views

Row-based iterative algorithms for computing the kernel of a matrix

Suppose $A$ is an $m \times n$ matrix in the form $$A=\begin{pmatrix} — a_1 —\\ — a_2 —\\ \vdots \\ — a_m — \end{pmatrix}$$ where $a_i \in R^n$ is the $i$-th row of $A$. I know that it is possible ...
Kamil Tog's user avatar
0 votes
0 answers
142 views

Jordan Decomposition of Sparse matrix

Suppose we are given $n \times n$ rational matrix, $A$ with at most $k$ nonzero elements in each row and each column with $k \ll n$. What is the best algorithm to compute its Jordan decomposition? ...
gondolf's user avatar
  • 1,503
0 votes
0 answers
52 views

How do I test two square matrices are transpose to each other if only the column vector summations are known?

Given two secret square matrices, say $\left( {\begin{array}{*{20}{c}} {{a_{11}}}&{{a_{12}}}&{{a_{13}}}\\ {{a_{21}}}&{{a_{22}}}&{{a_{23}}}\\ {{a_{31}}}&{{a_{32}}}&{{a_{33}}} \...
user67451's user avatar
1 vote
1 answer
310 views

Algorithm for checking positive definite matrix over a subspace

There is an algorithm that for any input matrix $A \in \mathbb{R}^n$ satisfies $x^\top A x>0$ for all $x \in \mathbb{R}^n$, e.g. by using Cholesky algorithm. Is there an algorithm that, for matrix $...
nivotko's user avatar
  • 21
0 votes
2 answers
556 views

Sparse dense matrix versus non-sparse dense matrix in eigenvalue computation

I have a matrix in the form of $2n\times 2n$ block matrix $$ A = \begin{pmatrix}O& W\\ J& D\end{pmatrix} $$ where, $O$ is an $n\times n$ zero-matrix; $W$ is a n-by-n diagonal matrix, $W = ...
Pascal's user avatar
  • 91