Talk:Costas array

Apparent conflict

All Costas arrays of size up to and including 26x26 are known. It is not known whether Costas arrays exist for all sizes. Currently, the smallest sizes for which no arrays are known are 32x32 and 33x33. ?? If I read this my conclusion would be that we know then up to 31x31. So why say whe know then up to 26x26. —Preceding unsigned comment added by 87.212.47.202 (talk • contribs)

These statements are not in conflict. The first statement says we have a complete list of Costas arrays of size 26×26 or smaller. The second statement says we know at least one Costas array for each size up to 31×31, but don't know any Costas array of size 32×32. Taken together, these claims imply that we know some of the Costas arrays of size 27×27 (say), but we don't know if we have found all of them yet. Michael Slone (talk) 01:44, 1 March 2008 (UTC)[reply]

Thanks for the quick reaction. I have red the article again and now have a much better understanding. Thanks. —Preceding unsigned comment added by 87.212.47.202 (talk) 18:17, 1 March 2008 (UTC)[reply]

Eponym?????

This article begins thus:

In mathematics, a Costas array can be regarded as....

It should say

In mathematics, a Costas array, named after ????? Costas, can be regarded as....

for the appropriate value of ?????. 05:24, 4 July 2008 (UTC)

John P. Costas, engineer active in the 1950s and 1960s. Unfortunately there is a CEO with the same name, so google is nearly useless. MathSciNet only has a single paper by him. http://www.costasarray.org/ is not terribly helpful for the biographical details. JackSchmidt (talk) 05:36, 4 July 2008 (UTC)[reply]

He's the John Costas who invented the Costas loop. There's some biographical data in a talk by Rickard [[1]] (who has interviewed Costas, so it's reasonably reliable) which I will use to make a page for him. Jhealy (talk) 12:51, 17 July 2008 (UTC).[reply]

Merger proposal

The article Welch-Costas array is very short and says little that is not already covered here. Richard Pinch (talk) 18:51, 17 August 2008 (UTC)[reply]

Done. Richard Pinch (talk) 21:10, 31 August 2008 (UTC)[reply]

Suggestion, add in Sudoku reference links

Sudoku grids are very much related to Costas Arrays. Same basic concept extended to a profitable "Casual User" amusement concept. — Preceding unsigned comment added by 75.134.108.144 (talk) 12:59, 7 February 2012 (UTC)[reply]

Numerical Representation?

The section on numerical representation gives a possible (used?) short-hand method for representing only the unique "y" coordinates of each column, from left to right, and the "y" coordinate being assigned 1 at the "bottom" of the array (matrix?) and increasing upward. While these are exactly the "x" and "y" coordinates as they would normally be assigned in a Cartesian plot, this is completely counter to the way that essentially all linear algebra texts I've ever experienced assign indeces. Indices (like i or j) would be assigned row first (i) then column (j) with i=1 being the top row and j=1 being the left-most column. So the linear vector assigned on the main page as {2,1,3,4} a la Des Cartes shuold probably be assigned more appropriately {4,3,1,2} a la row/column notation. Can anyone point to a linear algebra text that doesn't use this standard row/column notation? 65.202.226.2 (talk) 19:42, 5 March 2012 (UTC)mjd[reply]

Update links?

Some of the links to Beard are to files on a rented host space, but all those files have been moved to IEEE Dataport. The papers associated with them on Beard's website now have DOIs for the IEEE Dataport pages, but referring directly to IEEE Dataport seems preferable. -- motorfingers : Talk 00:39, 12 September 2024 (UTC)[reply]