21.txt

This complete matlab for neural network

发信人: yaomc (白头翁&山东大汉), 信区: DataMining
标  题: [合集]What the NP hard problem means?
发信站: 南京大学小百合站 (Fri Apr  5 12:59:25 2002), 站内信件

yaomc (白头翁&山东大汉) 于Wed Mar 27 10:51:26 2002提到：

Some people like to say the NP hard or easy problems, what the means about 
them, can anybody tell me ? thanks.

shutter (shutter) 于Wed Mar 27 11:20:05 2002提到：

a problem which can not be solved in a polynomial time with a confirm
 arithmetic


timeface (face) 于Wed Mar 27 11:24:29 2002提到：


NP – Complexity class of a decision problem which answers can be checked by 
      an algorithm whose run time is polynomial in the size of the input.  

Doesn’t require or imply an answer can be found quickly, only that any 
claimed answer can be verified or refuted quickly

NP Complete-  Informally, a problem is NP-Complete if an answer can be 
verified quickly, and a quick algorithm to solve this problem can be 
used to solve all other NP problems quickly

NP-HARD: When a decision version of an optimization problem is proven to 
belong to the class of “NP – Complete” problems, an optimization version 
is NP-Hard.  Since there is no easy way to determine the optimal solution, 
an NP-Hard problem is at least as hard as, or harder than, any problem 
in NP


boy (刘芳百是) 于Wed Mar 27 11:40:20 2002提到：

有关计算复杂性的书上都会讲这个问题
简单地说，无法在多项式时间内解决的问题称为NP问题


yaomc (白头翁&山东大汉) 于Wed Mar 27 11:46:54 2002提到：

If the meaning of NP is Not can be solved using the Polymanial?


boy (刘芳百是) 于Wed Mar 27 15:13:38 2002提到：

maybe


waterflower (农民上访工人下岗某些分子搞三讲) 于Thu Mar 28 17:54:44 2002提到：

NP nondeterminability polynomial非确定多项式
可能在多项式时间内完成，也可能没法完成，不确定