pi

I type Math.PI; in Chrome Console and this is returned: 3.141592653589793 Then I type Math.PI - 3.141592653589793; and 0 was returned. Is there a way to get a more accurate value (such as 3.1415926535897932384 ) of Math.PI in Javascript? The maximum decimal places in javascript is limited to 15 . So you cannot get more than 15 decimal places. But you can get up to 20 decimal places by doing but its not accurate Math.PI.toFixed(20); //3.14159265358979311600 That will give you a PI value with 20 decimal places. Note: 20 is the maximum and 0 is the minimum for toFixed() . So trying Math.PI

This question already has an answer here: Is floating point math broken? 30 answers This is something I wasn't expecting. I know these numbers are not 100% exact, but I wasn't expecting complementary angles giving different results of sin and cos : This following function returns 0.70710678118654746000000... sin(45 * PI / 180.0); while this follwing function returns 0.70710678118654757000000... cos(45 * PI / 180.0); so, it's: 0.707106781186547**46**000000... vs 0.707106781186547**57**000000... and not only those... sin(1 * PI / 180.0) also returns a slightly different number than cos(89 * PI /

I know that you can use: #define _USE_MATH_DEFINES and then: M_PI to get the constant pi. However, if I remember correctly (comments welcome) this is compiler/platform dependent. So, what would be the most reliable way to use a pi constant that won't cause any problems when I port it from Linux to other systems? I know that I could just define a float/double and then set it to a rounded pi value myself, but I'd really like to know if there is a designated mechanism. Meeting C++ has an article on the different options for generating pi: C++ & π they discuss some of the options, from cmath ,

I wanted to know how I can generate pi to the nth digit. I have a couple of basic ideas. Use Math.PI and increase the precision (if that's possible) Use Euler's formula to generate pi but even here, I would need to increase the precision (I think) There is also Srinivasa Ramanujan's formula for generating PI which is known for it's rapid convergence. This formula seems difficult to implement. I believe, I would have to also increase deicmal precision here. So in short, either way, I would need to increase the precision of BigDecimal depending on what the nth digit is. How would I go about

基于python的web server有很多，比如：django、web.py、tornado、fastcgi等。经过一番比较我选择使用tornado，使用tornado的原因有如下几个：1、tornado是轻量级的web server，2、异步I/O处理连接请求，3、tornado是facebook开源项目之一。由于我的raspberry pi使用的是raspbian操作系统，而raspbian操作系统源上有python-tornado和python3-tornado二进制包，所以直接使用命令$sudo apt-get install python3-tornado python-tornado完成安装。完成安装后使用tornado官方网站上提供的测试代码来测试web服务器是否好用。测试代码如下： #!/usr/bin/env python3 import tornado.ioloop import tornado.web class MainHandler(tornado.web.RequestHandler): def get(self, name): self.write("Hello, world") application = tornado.web.Application([ (r"/(.*)", MainHandler), ]) if __name__ == "_

上文写道如何在raspbian上使用TP-LINK TL-725N无线网卡，本文使用该无线网卡实现一个下载机。硬件平台：Raspberry pi。软件平台：操作系统使用raspbian，其他软件包括开源的aria2、webui-aria2以及nginx。aria2是linux平台下的“迅雷”，支持多线程下载、断点续传、支持Http(s)、FTP、BT和Metalinks。由于raspbian源上有aria2，所以直接使用命令$sudo apt-get install aria2来安装aria2。nginx是一个轻量级的、支持高并发的http服务器，广泛的应用在大型服务器的前端以及直接用于小型服务器。由于raspbian源上有nginx，所以直接使用命令$sudo apt-get install nginx来安装nginx。安装完nginx后，在PC机上使用浏览器访问 http://xx.xx.xx.xx:80，若出现Welcom e to nginx!则表示raspberry pi上的http服务器启动成功。webui-aria2是一个开源的aria2的web前端，webui-aria2与aria2通过rpc相互通信。webui-aria2可以在https://github.com/ziahamza/webui-aria2下载。下载完成后将解开的目录内容复制到/usr/share

香蕉派 banana pi github 最新Linux 代码升级到kernel 4.2. https://github.com/BPI-SINOVOIP/BPI-Mainline-kernel ，以后4.2的内核将作为香蕉派开源硬件的稳定支持版本。现在已经在解决了WIFI兼容性问题，有兴趣的开发者可以自行下载编译自己的镜像 来源： oschina 链接： https://my.oschina.net/u/1177513/blog/502295

Banana PI BPI-M2 是一款四核高性能单板计算机，Banana PI BPI-M2是一款比树莓派更强悍的四核Android4.4产品。 Banana PI BPI-M2兼容性强大,可以跑android系统,Debian linux,Ubuntu linux, Raspberry Pi系统 和 cubieboard 系统. Banana PI BPI-M2硬件：1Ghz ARM7四 核处理器，1GB DDR3内存，千兆以太网口，4 USB 接口 流畅运行Android4.4。Banana PI BPI-M2体积如信用卡大小，与BPI-M1尺寸一样，但接口有不同，轻松运行《雷神之锤三：竞技场》这样的游戏，支持1080P高清视频输出，GPIO兼容Raspberry PiB+并能运行其ROM Image。 来源： oschina 链接： https://my.oschina.net/u/1177513/blog/372749

香蕉派 banana pi BPI-M2_WiringPI 测试成功，代码已经上传到GITHUB BPI wiringpi 由树莓派最新的WiringPi代码修改过来，完全与树莓派的使用方法一样。 GPIO库与测试代码完全公开在GITHUB上： https://github.com/BPI-SINOVOIP/BPI-WiringPi/tree/BPI_M2 演示视频： http://v.youku.com/v_show/id_XMTMxMjA1NTY3Mg==.html?from=y1.7-1.2 中文论坛： http://forum.banana-pi.org.cn/thread-709-1-1.html 来源： oschina 链接： https://my.oschina.net/u/1177513/blog/493619

在香蕉派 Banana Pi BPI-M1上使用 开源 OxOffice Impress 在Banana Pi BPI-M1上使用OxOffice Impress，該簡報大小約26MB，採用自動播放機制。 OxOffice提供 arm linux的版本，可佈署在arm linux系統上使用，晟鑫科技也提供相關的文件相容性修正及專案開發服務。 http://v.youku.com/v_show/id_XMTMyMTI2NTQyOA==.html?from=y1.7-1.2 来源： oschina 链接： https://my.oschina.net/u/1177513/blog/498730