What does ponder means in engines?

I have been trying to install various engines in my Arena GUI and saw an option named ponder.What is it? And what should I do with it?

No 1 can help u here

sorry!

ponder means the engine will think on your time.  (Or, if two engines are playing each other, if one engine has ponder=on it will think when the other engine is thinking.

Normally you leave ponder off when playing engine vs engine tournaments.

http://www.horizonchess.com/FAQ/Winboard/computer.html

Ponder ON or OFF?

Pondering refers to the fact that very the engine has moved, it will continue to "think" [on the assumption that the opponent will play what it considered the best move] just as humans do. There are some who feel that Pondering should be set OFF when testing on one computer. This ensures that when it's programs A's turn to move we can be sure that all the computer resources are used by A and A alone.

On the other hand, some argue that a engine that is crippled by turning off pondering, is a totally different animal from the one that authors work with since they usually test with ponder on, on one computer.

Crafty for example has time management that is based on the assumption that Pondering is on. As such if it accurately predicts the opponent's moves during pondering, it will save time later. If pondering is not turned on, this will not happen, and Crafty will spend too much time on the moves early in the game and get into time trouble later. Thanks to Tim Mann for explaining this] It is also unknown if setting Ponder off will hurt some engines like Crafty more than others. There have being attempts by some to show that setting Ponder-OFF effects all programs equally, [Noticeably, tests by Volker Pittlik , show that the results are similar whether Ponder on or OFF are used], but neither side remains convinced. [E.g. Volker tested Crafty with a series of strong freeware programs , but it is arguable that the weakness that affects Crafty due to pondering would only be apparent against Stronger commercial programs].

In some cases, you will have games where one program doesn't support pondering at all playing against one that supports pondering. In that case if you are running the match on one computer, it would be advisable to turn pondering off since the CPU usage would be extremely uneven. On two computers , the program that can ponder should be allowed to ponder. The lack of pondering in one engine shouldn't handicap the other, unless there are serious reasons against doing so. [See the discussion about book learning] [Thanks to Severi Salminen for pointing this out]

Wait, aren't there ways to limit the resources each engine can use. Like humans, they should be given consisetient all time processing power to use as they wish. Is this technically feasiable?

By enable pondering you practically halves the available cores for each engine, with the benefit of thinking on opponents time.

For example 4 cores at 100% usage work better than 2 cores at 100% for both engines.

Poundering should be used mainly in engine matches with two computers linked together for increased overall strenght. Full processing usage even on opponents time.

Permanent brain is estimated to increase the strenght by ~30-50 particularly on two-machine matches.