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implement more constructions for Hadamard matrices, e.g. for size 116 #34690
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Author: Matteo Cati |
Commit: |
Branch pushed to git repo; I updated commit sha1. New commits:
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comment:5
Added Williamson construction, together with data for creating hadamard matrices of order 116 and 172 using this construction. |
Dependencies: #32267 |
Branch pushed to git repo; I updated commit sha1. New commits:
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comment:8
OK, good. The 1st and 2nd smallest value for which we don't have an implementation. 156 was first constructed in https://projecteuclid.org/journals/bulletin-of-the-american-mathematical-society/volume-71/issue-1/A-new-construction-for-Hadamard-matrices/bams/1183526410.full 236 is the 3rd. For 188 there is https://arxiv.org/pdf/0704.0640.pdf - but most probably it's not the 1st such a construction. |
comment:9
Do we always mean return a normalised Hadamard matrix? Note that
which is done with |
comment:11
Please also check whether new matrices at #32267 work with |
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
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comment:13
Replying to Dima Pasechnik:
This error was already present in #32267, so I fixed it in that ticket and then rebased this one. |
comment:14
rebased over latest beta, slight reference fix Last 10 new commits:
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Reviewer: Dima Pasechnik |
Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:
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comment:31
In docstrings, please keep Hadamard capitalised. |
Branch pushed to git repo; I updated commit sha1. New commits:
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comment:33
The next construction that can be implemented is the one described in https://core.ac.uk/download/pdf/82189436.pdf, which will give new Hadamard matrices for many different orders (including 292, which is the smallest value currently missing). |
comment:34
OK, great. For comment:33 constructions, please open a follow-up ticket. How far will we be from 668 (the 1st 4k for which existence of a matrix is unknown) then? |
Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:
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comment:36
Replying to Dima Pasechnik:
After implementing the construction in comment:33 the missing orders will be 412, 428, 452, 476, 508, 532, 604, 612, 652 but it should be possible to implement all of them just by adding more data (T-sequence and williamson type matrices) to the constructions that are already present. |
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
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comment:38
I've created the next ticket: #34807 |
comment:39
Could you replace |
Branch pushed to git repo; I updated commit sha1. New commits:
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Changed branch from u/gh-MatteoCati/add_hadamard_matrices_constructions to u/dimpase/add_hadamard_matrices_constructions |
comment:42
looks good. |
Changed branch from u/dimpase/add_hadamard_matrices_constructions to |
…r 664 With sagemath#34690, all the Hadamard matrices of order <=288 have been added. The next task is to implement matrices of order up to 664 (668 is the first order for which no construction is known). This will require implementing https://core.ac.uk/download/pdf/82189436.pdf, as well as adding some more data for the constructions that are already present. URL: https://trac.sagemath.org/34807 Reported by: gh-MatteoCati Ticket author(s): Matteo Cati Reviewer(s): Dima Pasechnik
With #32267 done, the next not yet implemented construction is for n=116. This was originally constructed by Williamson,
cf e.g. Marshall Hall's book https://onlinelibrary.wiley.com/doi/book/10.1002/9781118032862
Implementing Williamson construction would be a natural way here.
Depends on #32267
CC: @MatteoCati
Component: combinatorics
Author: Matteo Cati
Branch/Commit:
bd025a2
Reviewer: Dima Pasechnik
Issue created by migration from https://trac.sagemath.org/ticket/34690
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