magicblue-CSDN博客

原创 Boost Graph Library 学习笔记

最近研究了一下boost graph library(简称BGL)。由于文档的过于简略和使用者数量较少，一时半会弄明白还不是那么简单的一件事情。网上也有不少入门文章，这些我就不再说了，主要说一下我遇到的一些问题。 1. descriptor 和 iterator的区别BGL里有2种迭代器性质的东西，分别是descriptor和iterator。在STL里只有一种迭代器，就是iterat

2009-05-22 15:34:00 8396 2

原创从C++与Unicode说开去

以前遇到过这么一个问题，用C++序列化一个wstring。程序很简单，因为C++有wofstream：std::wstring str = L"s"; std::wofstream ofile("F://test.txt"); ofile 我使用的编译器是VC9，wchar_t是2字节。那么test.txt就应该是unicode的宽字节，其大小应该是2字节。但是实际的结果却是1字节

2008-02-01 23:51:00 2389

原创据说是一道百度的笔试题

在论坛上看到有人问这个，觉得其中一个有点意思就回了。顺便把回的内容发在这里。题目是这样的：///////////////////////////////////////////////////////////////////// answer beginning //////////////////////////////////////////////////////////////

2008-01-25 16:28:00 1156 2

原创扩展A*算法

A*算法作为一种启发式寻路算法比一般的shortest path finding比如dijkstra算法更快，但是由于启发式的原因，其结果不一定是最优的。只有在一定的条件下，A*算法才能保证找到最优解。这个条件是A*算法的启发式h(n)必须是consistency或者monotonicity的：A heuristic h(n) is consistent if, for every

2008-01-05 10:43:00 1416

原创 boost在vc9(vc2008)下的安装

这几天写代码需要序列化自定义类，类的定义可以抽象为vector >。我本想通过重载operator> 来实现序列化。但是写入是写入了，读就读不出来了。在读完第一个对象之后istream的tellg()返回了-1，导致后续的对象无法读取。后来我使用boost很方便的就完成了序列化的工作。但是我使用的编译环境是VC9，boost还没有针对vc9的编译设置，所以编译安装还是花了点时间。针对VC9，下

2007-12-19 21:38:00 6918 4

原创《Chomsky: ideas and ideals》笔记

Connectionism的基础是把语言看成技能和习惯的行为主义。Connectionism的致命弱点是它不依赖结构，而语言是有自身结构的。语言习得靠语言结构。Chomsky的理论基础和语言的随机产生初看起来相背离，但是实际上它们并不相关。语言自产生初期到现今，人类已经经历了150万年的进化。在这段时期，进化的力量可以产生很明显的效果：DNA发生变化，使大脑进化出某种结构。Chomsk

2007-07-24 01:28:00 1767 2

原创搜索之路在何方

互联网是一个真正改变人们生活方式的发明，与这种改变相提并论的恐怕得拿出电气化了。互联网最初是一个军方项目，但是在民用化之后，其中的信息量不停的增长。随之而来的问题则是如何在海量的信息中找到你所需要的信息，这很重要。搜索技术的发展时间很短，大概只有十多年。直到今天，搜索技术在本质上仍旧是最开始的关键词匹配。获得高质量的查询结果关键在于你要以机器的方式去思考应该如何写出那几个查询词，如

2007-07-24 01:24:00 794

原创奥卡姆剃刀

奥卡姆剃刀是一个哲学原理，是由经院哲学家奥卡姆提出的。这个原理十分简单：“如无必要，勿增实体”。这不是科学原理，因为这个说法是无法证明的。和数学一样，在一次又一次对自身的验证中，你只需相信它。这个原理被现代科学广泛的使用，在这样一个背景下，更详细的说法是：“给定一观察数据和若干种描述观察数据的理论，优先选择最简单的理论”。我举个简单的例子：给定一个观察数据，一个

2007-06-22 22:24:00 1299

原创 Language model of IR

Traditional IR is divided into 2 parts: index and retrival. Things connect them is words counts: tf and idf. Whatever models traditional IR is(vector, probabilistic...), the core context of repres

2007-05-11 11:57:00 1142

原创 Notes about NLP and IR

NLP introduces First Order Predicate Calculus to implementing meaning of our languages, however this method cant completely express the meaning understanded by ourselves because machine has not perce

2007-03-31 22:37:00 734

原创 the initialization of ANN weights and activation function

the chioce of weights initialization and activation function is a paradigm: 1. weights must be small suitablely at random(too small is bad). 2. activation function is supposed to be linear in range of

2007-02-17 16:58:00 1058

原创 Fitness function

I am always thinking about the fitness function, its a natural selection pressure simulation with a little bias. the difference between them is that for a given problem, fitness function for it is st

2007-01-22 11:57:00 1728

原创 A tag of infinite

infinite is a important concept in programming. the following is a class which implements this concept.template // T was supposed to be legal number typesclass neg_infinite{public: explicit neg_i

2007-01-09 15:52:00 877

原创 Bayes optimal

as its name, bayes optimal decision is the best decision over all decisions, however it is impossible to working out solutions because it requires to summing out all hypothese. you cant obtain ALL hy

2007-01-05 23:36:00 1012

原创 Rethinking "A refinement..."

a paper "Hierarchically classifying documents using very few words" gives a better explanation about the question why refinement works without overfitting. this paper proposes a new classification met

2006-12-31 13:58:00 753

原创 Thinking about a paper "A Refinement Approach to Handling Model Misfit in Text Categorization"

in this paper, i think the most interesting thing is why there is no overfitting? overfitting is inevitable when training on training examples too much. because decision line(surface) fits specifi

2006-11-30 19:01:00 852

原创 Why evolution involves sex?

the author of > David Ruelle says: "because adds is significant". interesting viewpoint! the difference between sexual reproduction and asexual reproduction is the process of DNA does crossover or not

2006-10-25 23:14:00 1270

转载 With or Without You

With or Without YouU2See the stone set in your eyesSee the thorn twist in your sideI wait for youSleight of hand and twist of fateOn a bed of nails she makes me waitAnd I wait.... without you看见你眼里坚硬

2006-10-13 20:36:00 855

原创 Measures of information

may be the measures of information has many ways, just like distance can be defined in many ways. how to describe a human-being? you have to admit this job is very diffcult in a "normal" way, or you

2006-10-10 14:37:00 937 2

原创 Language and Wittgenstein

first of all, consider two problems:1. given a family which has two children, one of them is a boy, what is the probability of other child is a boy?most people give the answer 1/2, but it is inco

2006-09-09 00:10:00 852

原创 The essence of universe

That is discreteness. I guess movement is discrete from Zenos paradox -- you never catch up a tortoise several years before, but today i suddenly realize the time also is discrete. This is apparent b

2006-08-26 01:00:00 1023

原创 What things is chaos can't change?

Chaos or the sensitive dependence on initial condition can result in very different outcome given a almost same initial condition. A well-known example is butterfly effect. Chaos has excellent ability

2006-08-22 13:39:00 734

原创 Using SOM to get a feature in a file

Crack a game is not an easy thing, especially protected by starforce. Starforce is powerful game protection tool, crack it is a difficult task. It will detect the CD-ROM, and validate the CD is a

2006-08-03 17:38:00 1162 1

原创 0,1 bits random string generating

According to information theory, a real random string can not be compressed. So I think there is a random string generating method which is compress a document until its size decreasing proportion

2006-08-02 11:58:00 752

原创 Ideas about MMORPG

Nowadays MMORPG(Massively Multiplayer On-line RPG) has been limited by nowadays technology. What’s the advantage of MMORPG? The answer should be interaction. Unfortunately, this poor interaction i

2006-07-17 17:15:00 679

原创 Computing with huge integer

This article is came from a discussion in forum, it is a problem to computing f(n) that f(n) = fibonacci[i-1]*fibonacci[i]*fibonacci[i+1]. Apparently the vaule of f(n) is too huge to represented by p

2005-07-06 18:17:00 1003 2

原创 An attempt of “1 generates others 7” characteristic

I have tried to utilizing the “1 generates others 7” characteristic of n queen problem. Finally, I found that it must have the knowledge of relationship between n and numbers of solutions. The program

2005-04-18 12:15:00 861

原创 Utilizing symmetry characteristic of n queen problem

Given a solution and image the chess board is transparent. Another solution can be got immediately by turn this chess board (left-right turn). That is, look the solution from other side of chess board

2005-04-12 12:23:00 1006

原创 Space and time trade-off in n queen problem

The backtracking algorithm of n queen problem can be improved by space and time trade-off further. The consideration of positions occupancy is attained by duplicate_array and two integrals. Note that

2005-04-10 23:08:00 986

原创 Optimization of BackTracking algorithm for n queen problem

I think it is necessary to analyze the efficiency class before optimize it. It is difficult to estimate the efficiency class accurately because the each of recurrence running time is different. So I u

2005-04-07 19:27:00 1816

原创 The BackTracking algorithm for n queen problem

The article is about the design of algorithm for n queen problem. The intention of this article is from an excise of an algorithm book: >. This backtracking algorithm is interesting, so I decide to re

2005-04-06 00:55:00 2473

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