Sage - Online Mathematical Software

Sage is an mathematical software, the coolest point is it can run with any web browser.

I tried a sample plot function below, the usability is awesome too!

x=var('x')
plot(-0.3+(x+0.6)^0.5, (0,100))

Benchmarks for mt_rand() and rand()

Benchmarks results as below:

mt_rand() 10000000 times for 4.7026278972626 seconds
each one average is 0.00000047 seconds
rand() 10000000 times for 4.7438910007477 seconds
each one average is 0.00000047 seconds

The test machine is Amazon EC2 High-CPU Instances (20 ECU)

Another test as below:

mt_rand() 10000000 times for 2.4974269866943 seconds
each one average is 0.00000025 seconds
rand() 10000000 times for 2.4646849632263 seconds
each one average is 0.00000025 seconds

The test machine is Amazon EC2 Micro Instances (1 ECU)

CentOS install node.js

Basically, follow the installation guide in the node.js GitHub wiki page. I use the "Building from source" guide. Then install npm, follow the guide too, just easy type with "curl http://npmjs.org/install.sh | sh"

When I test nmp installation (install express), I found that I should type 'npm install -g express', and the express will be installed in the directory which I want. Otherwise, nmp will install locally (such as: ./node_modules/).

Install PHPUnit on Windows 7

First you need install a Zend Server in C:\Zend folder

Install Pear

Run commands below

# pear channel-update pear.php.net
# pear upgrade pear
# pear channel-discover pear.phpunit.de
# pear channel-discover pear.symfony-project.com
# pear channel-discover components.ez.no
# pear clear-cache
# pear update-channels
# pear install --alldeps phpunit/PHPUnit

DONE!

32bit 系統下 json_decode 遇到 BIGINT 的問題

在 32bit 系統下處理 Facebook 的 uid 時, 一定會遇到 json_decode 時, php 把 uid 轉成 float 的情形, 大部分的情形只要把 uid 轉成 string 就能做其他的事了, 以下是正確的轉型技巧

$json = '{"uid":100000123456789}';
$arr = json_decode($json, true);
// $arr = array(1) {
//   ["uid"]=>
//   float(1.0000012345678E+14)
// }
$s2 = sprintf ( "%.0f", $arr['uid'] );
// $s2 = string(15) "100000123456789"

How to login with Administrator account in Thinkpad

単純にadminでログインしたいだけであれば以下の手順でできます。

1. 「ユーザーアカウント制御設定の変更」からUACを無効化
2. OS再起動
3. コマンドプロンプトを起動し以下を入力
   net user administrator /active:yes
4. 「ユーザーアカウント」にadminが出ることを確認

resource: http://bbs.kakaku.com/bbs/K0000092865/SortID=11470155/

jQuery file upload plugin: AjaxFileUpload

We can use AjaxFileUpload make a file upload process.

Basic usage:

function ajaxFileUpload()
{
  $.ajaxFileUpload({
    url:'upload.php',
    secureuri:false,
    fileElementId:'fileToUpload',
    data:{name:'logan', id:'id'},
    success: function (data, status) {
      alert($(data).text());
    }
  });
  return false;
}

Official Guide have more detail usage.