Timeline for Lp norm of Hadamard matrix
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 5, 2021 at 13:55 | comment | added | J.J. Green | There is a method (by Stephen Drury) which gets the $\ell_p \rightarrow \ell_q$ operator norm of a matrix to arbitrary accurately using a global subdivide-and-reject method, but is exponential in matrix size so $10 \times 10$ is about as far as you can go: His implementation is here: math.mcgill.ca/drury/research/matsaev/matsaev.html and I made a stab at the same algorithm in C soliton.vm.bytemark.co.uk/pub/jjg/en/code/steckin | |
| Oct 5, 2021 at 13:47 | comment | added | Willie Wong | Thanks; that's pretty neat. | |
| Oct 5, 2021 at 13:17 | comment | added | J.J. Green | A variant power-method which is I believe equivalent to a local optimisation (hence always a lower bound on the value), details here: link.springer.com/article/10.1007/BF01396242 | |
| Oct 5, 2021 at 13:00 | comment | added | Willie Wong | Incidentally, I am curious how Octave computes the matrix norms. Do you have a link to what Higham's approximation does? (I tried Googling, but not being an expert cannot really find it among the other results about approximation and algorithms linked to that name.) | |
| Oct 4, 2021 at 22:51 | history | edited | J.J. Green | CC BY-SA 4.0 |
constant -> equal
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| Oct 4, 2021 at 19:21 | comment | added | Willie Wong | You are right! (In my defense, I took $\|H\|_{\infty}$ from the OP's question without checking whether it was correctly computed.) | |
| Oct 4, 2021 at 10:15 | history | answered | J.J. Green | CC BY-SA 4.0 |