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3 votes
1 answer
332 views

Complexity of inverting and multiplying against a symmetric Toeplitz matrix with two repeated entries

I know that the computational complexity of inverting a general $n \times n$ matrix $A$ is $O(n^{2.373})$ and multiplying it against an $n \times m$ matrix is $O(n^2m)$. Moreover, I've seen that ...
Annie's user avatar
  • 91
17 votes
4 answers
6k views

Why is fast matrix multiplication impractical?

I am wondering why fast matrix multiplications are impractical, especially for Boolean matrix multiplication. I read some content saying fast matrix multiplications are impractical because of large ...
Jiawei Ren's user avatar
6 votes
2 answers
2k views

Complexity of rectangular matrix multiplication

I am interested in the complexity of multiplying two matrices $A$ and $B$, i.e. to compute $AB$. From [Le Gall and Urrotia], I know that: if $A$ and $B$ are square-matrices of size $n$, then this can ...
N. Gast's user avatar
  • 562
21 votes
2 answers
18k views

Complexity of linear solvers vs matrix inversion

Solving linear equations can be reduced to a matrix-inversion problem, implying that the time complexity of the former problem is not greater than the time complexity of the latter. Conversely, given ...
Alm's user avatar
  • 1,207
9 votes
1 answer
1k views

Computation time of Smith normal form in Maple

I am using Maple to compute the Smith normal form (SNF) of a $120 \times 120$ matrix and it seems that I will never get an answer back. I have checked my code for small cases and I believe that it is ...
Yibo Gao's user avatar
  • 356
58 votes
2 answers
18k views

How fast can we *really* multiply matrices?

Background: The Strassen Algorithm, described here, has a computational complexity of $\text{O}(n^{2.807})$ for the multiplication of two $n \times n$ matrices (the exponent is $\frac{\log7}{\log2}$). ...
Vidit Nanda's user avatar
  • 15.5k