Talk:Bitboard

message: Are most chess bitboard engines rotated?  Does anyone have information on this or can lend an expert opinion?
- A question: Why is it said about a dozen times that implementing a bitboard is rather hard to do? There are a lot of things that are difficult (look at all of the math articles) but i think Wikipedia should be informative, rather than rating the stuff...
Anyone agree?
:Yes, I agree. In general, this article is written in a very casual style that in not encyclopedic. Rm999 02:40, 30 April 2006 (UTC)
thread_title: Rotated bitboards

message: Glen Pepicelli, I hadn't considered my changes controversial. I think that it's obvious in a section called "Pros" in an article about bitboards that you're describing the advantages of bitboards, so I removed the redundancy. What was unclear in my new text? -Slamb 05:34, 15 August 2006 (UTC)
thread_title:  Why the revert? 

message: The illustration depicts 12 bitboards (2 each of the six types of pieces in the game: Pawn, Rook, Knight, Bishop, Queen, King).  But the text says "10 boards" at 64 bits each --- which is 768 bits ... or 96 octets --- bytes. —The preceding unsigned comment was added by JimD (talk • contribs) 04:58, 3 May 2007 (UTC)
thread_title:  Text Inside Illustration is WRONG 

message: No, they are not, you can store a position in a single Byte, use that for all non-pawns, you will need 16 Bytes, instead of 80 Bytes (+16 Bytes for the pawns each). And of course it can even be more compact… (I am ignoring promotion, but in most games there is no promotion, thus it could be handled as special case) --Chricho ∀ (talk) 17:53, 3 July 2011 (UTC)
replies: text: You are correct - considering the number of bitboards needed, one for each piece's attacks or moves, and one for each space for piec es attacking that space (that's 64 boards = 4096 bits or 512 bytes), 2 for king locations, and usually others.  The purpose of bitboards isn't compactness, but execution efficiency, since many loop-and-compare operations are reduced to bit (AND, OR, NOT) operations. I'll adjust the text to reflect the use. Sbalfour (talk) 16:47, 10 May 2019 (UTC)
thread_title:  “Bitboards are extremely compact.” 

message: There are a few other uses for bitboards that would fit in this article, I think.  I have come across 2 papers that make use of them
http://link.springer.com/chapter/10.1007/978-3-642-32527-4_49 - to do with robotics (theres a thesis as well by the same author, but that's quite long)
Segundo, P.S., Galan, R., Matia, F., Rodriguez-Losada, D., Jimenez, A.: Efficient Search Using Bitboard Models. In: Proc. 18th IEEE Int. Conf. Tools with A.I., pp. 132–138 (2006) - to do with solving mathematical graph problems efficiently.
thankyou.  — Preceding unsigned comment added by 193.117.31.2 (talk) 14:51, 30 October 2014 (UTC)
thread_title:  other uses 

message: At Wikipedia, they have same definition. Except "Bitboard" defined as "commonly used in chess".
AFAIK, we don't have sources for "Bitboard", then can we merge them?
Distinction between
* Bit field (single bit)
* Bit word (aligned to Computer word)
* Bit array (software implementation of multiple bit fields)
was shown at Bit field page. Ushkin N (talk) 07:48, 28 May 2016 (UTC)
replies: text: They are different topics and should remain distinct articles. It would violate WP:UNDUE to merge this content to bit array (there is too much of it in proportion to its importance to bit arrays in general) and on the other hand if it were redirected without merging then it would be useless as an explanation of the bit board programming technique (what do the bits mean?). —David Eppstein (talk) 00:36, 29 May 2016 (UTC)
thread_title:  Distinction from [[Bit array]]? Merge it please 

message: There are a lot of technical details omitted from the article.
* exactly what does it mean to rotate a chessboard 45 degrees (or 135 degrees)?
* how do you do that at the bit level?  It's conceptually mapping 64 bits to 64 other bits, and therefore 64 sets of shift/AND/OR instructions will do it, but a sequence like that is likely to invalidate the whole method, because it's slow, and a loop of such instructions is way way worse
* why is a perfect hash function a bane rather than benefit to magic bitboards? though I've not exactly read this anywhere, it's experimentally evident 
* as a practical matter, incremental update of bitboards is required, otherwise regenerating them on a per node basis makes the representation slower than mailbox; generally, you need to be very technically proficient coding bitboards, or you're better off with the short, simple, and readily optimized mailbox implementation
Sbalfour (talk) 00:14, 17 September 2019 (UTC)
thread_title:  Technical details elided