The Best Image Ever That Illustrates High-Order Functions Clearly

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Saw this image while surfing the internet. This is far more the best image that illustrates the high-order functions (map, filter, reduce), which works for all programming languages. Check it out! Copied from HERE.

VS2013 Regular Expression Bug? Maybe

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I was trying to parse a large file with blocked data using regex library in VS2013. By working in 2 sites, I installed gcc on my Linux machine and VS2013 on Windows. The expression is very simple as "START_INFO[here is the tricky bit]END_INFO", where each block is clearly enclosed by its own start and end information. Inside the [] (square brackets) I'd like to match ALL valid characters. The . (dot) matches almost all but not the newline character and it becomes literal inside the square brackets []. So I came up with an alternative solution "[\s\S]+?" which should guide the program to search all whitespace and non-whitespace characters until it reaches the END_INFO.

C++ I/O Tips: Saving Huge Text File using Boost Library

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以前这篇文章写过利用Boost的内存映射来读取超大文件,但是读取的目的最终还是要写入结果文件.网络上使用Boost来读取文件的例子不少,但是写文件的例子则寥寥无几.记录一下,以备将来使用.

Tetrahedron Properties

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做CFD与FEA分析,经常要与网格打交道.而FEA分析最常用的网格大概就数四面体网格了(tetrahedron).无论是4-node还是10-node,其几何形状都是经典的三棱锥.本文记录一些用到的四面体属性知识.

C++ I/O Tips: Parsing Huge Text File

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问题提出

最近项目需要读取mesh文件,基本做过CFD的都知道,几千万Elements的mesh文件动辄几个Gb,庞大的体积让各种操作都很不方便.而获取数据需要与磁盘打交道,作为后续处理的第一步,是一切的开端.如果需要读取的文件是二进制格式,会有些帮助.但是不同的网格划分软件大都有其自有格式,等于是带着枷锁跳舞.

注意:这里的测试使用的都是文本文件,可能不适用于二进制文件读写.

下文使用的开发环境: VS2013 + Win10 + i7 CPU/16G Ram.
测试数据是ICEM导出的Star-CD的vrt格式.这种格式可以看作是文本文件,每一行一组数据表示一个Node(也就是一个三维点): Node_ID X Y Z.Mesh有多少个Node,文件就有多少行.

Get Matlab Version

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Matlab provides loads of useful functions for scientific computing. However, the functions might be added or deprecated from version to version. To write more robust codes, it's always a good practice to deal with different cases. An if...else... clause would be enough for this purpose.