今天做作业,要实现整数线性规划的分枝定界法算法.找了一些网上的博客,发现都很屎,感觉自己写的这个比较清楚.规范,所以在此记录.如有错误,请指正. from scipy.optimize import linprog import numpy as np import math import sys from queue import Queue class ILP(): def __init__(self, c, A_ub, b_ub, A_eq, b_eq, bounds): # 全局参数 s
Outline 前言 Example-1 Example-2 运行说明 00 前言 前面一篇文章我们讲了branch and bound算法的相关概念.可能大家对精确算法实现的印象大概只有一个,调用求解器进行求解,当然这只是一部分.其实精确算法也好,启发式算法也好,都是独立的算法,可以不依赖求解器进行代码实现的,只要过程符合算法框架即可. 只不过平常看到的大部分是精确算法在各种整数规划模型上的应用,为此难免脱离不了cplex等求解器.这里简单提一下.今天给大家带来的依然是branch and b
00 前言 之前一直做启发式算法,最近突然对精确算法感兴趣了.但是这玩意儿说实话是真的难,刚好boss又叫我学学column generation求解VRP相关的内容.一看里面有好多知识需要重新把握,所以这段 时间就打算好好学学精确算法.届时会把学习过程记录下来,也方便大家学习! 01 什么是branch and bound(定义)? 1.1 官方一点[1] Branch and bound (BB, B&B, or BnB) is an algorithm design paradigm fo
Python中的描述符是一个相对底层的概念 descriptor Any object which defines the methods get(), set(), or delete(). When a class attribute is a descriptor, its special binding behavior is triggered upon attribute lookup. Normally, using a.b to get, set or delete an att
Python 安装包去官网自行下载: https://www.python.org/downloads/mac-osx/ Mac os 自带python, 但我记得是python2.7版本 在选择安装包时候避免使用太新的版本. 配置环境: $ vi ~/.bash_profile 增加如下配置 #python Set # Setting PATH for Python 2.7 # The original version is saved in .bash_profile.pysave PATH
00 前言 branch and cut其实还是和branch and bound脱离不了干系的.所以,在开始本节的学习之前,请大家还是要务必掌握branch and bound算法的原理. 01 应用背景 Branch and cut is a method of combinatorial optimization for solving integer linear programs (ILPs), that is, linear programming (LP) problems whe
00 前言 相信大家对branch and price的神秘之处也非常好奇了.今天我们一起来揭秘该算法原理过程.不过,在此之前,请大家确保自己的branch and bound和column generation的知识务必过关,而且是非常熟悉的那种.因为branch and price算法就是branch and bound和column generation的结合体. 01 应用背景 branch and price是组合优化中的一种常见方法,是用于求解大规模(变量数目很多)的integer
I am Nexus Master! The 13th Zhejiang University Programming Contest 参见:http://www.bnuoj.com/bnuoj/problem_show.php?pid=29137 题意就理解错了!!! 之后乱搞就也错了!!! Current Server Time: 2013-08-30 23:29:55 I am Nexus Master! Time Limit: 2000ms Memory Limit: 65536KB
找规律水题... Traveling Cellsperson Time Limit: 1000ms Memory Limit: 65535KB This problem will be judged on UESTC. Original ID: 185264-bit integer IO format: %lld Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type:
状压DP... Kings on a Chessboard Time Limit: 10000ms Memory Limit: 65535KB This problem will be judged on UESTC. Original ID: 185164-bit integer IO format: %lld Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type:
Query on a tree Time Limit: 5000ms Memory Limit: 262144KB This problem will be judged on SPOJ. Original ID: QTREE64-bit integer IO format: %lld Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type: None Graph
链接:http://www.bnuoj.com/bnuoj/problem_show.php?pid=25585 Current Server Time: 2013-08-27 20:42:26 Robots on a grid Time Limit: 3000ms Memory Limit: 65536KB 64-bit integer IO format: %lld Java class name: Main Prev Submit Status Statistics Disc
绘制了一张导图,有不对的地方欢迎指正: 下载地址 机器学习中,特征是很关键的.其中包括,特征的提取和特征的选择.他们是降维的两种方法,但又有所不同: 特征抽取(Feature Extraction):Creatting a subset of new features by combinations of the exsiting features.也就是说,特征抽取后的新特征是原来特征的一个映射. 特征选择(Feature Selection):choosing a subset of all
Cellphone Typing Time Limit: 5000ms Memory Limit: 131072KB This problem will be judged on UVA. Original ID: 1252664-bit integer IO format: %lld Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type: None Graph