Ads removed from the pastie. \o/
Running costs stayed. :-(
Donations welcome!

Bitcoin: 1QC38uPBSy7WSYz1whM5SYTHAdhqkN6o8V
Ethereum: 0x0855778a6181a69cc7d5d08c71c4f5846010eb67
Verge: D8fo1fszrNmUK4kfQW5owhYMv3osPvgn2g
Recent entries
2020-07-12 18:13:16
ert rttyuiu
2020-07-12 18:11:14
https://www.facebook.com/...
2020-07-12 18:11:03
FULL! Watch 365 DNI 365 D...
2020-07-12 18:10:08
creds
2020-07-12 18:09:38
kigaitsuze
2020-07-12 18:08:58
sdfsdfdsfsdfsdf
2020-07-12 18:05:07
[Sleduj] V síti (2020) C...
2020-07-12 18:04:04
https://www.residentadvis...
2020-07-12 17:58:35
zxczxc
2020-07-12 17:49:38
tsuburumashi
Permanent entries
2014-10-14 21:12:28
Boost property tree - Ite...
2013-10-18 08:24:21
Resize images in a folder...
2013-04-29 17:23:35
Find bad words in a text,...
2013-02-12 20:26:45
Merge two boost property ...
2012-12-18 16:21:40
OpenCV: Access/modify ima...
2012-11-19 10:48:40
Reading a boost::property...
2012-04-10 00:11:46
Convert hex to string or ...
2012-02-18 00:12:04
Screw up []-operator for ...
2012-02-16 03:02:24
Merge continuous numbers ...
2012-01-18 22:26:01
(PHP) Generate / Create (...
2011-04-19 16:05:25
Calculate one's age in ye...
2011-04-18 15:26:45
(PHP) Generate / Create r...
2010-08-26 15:18:00
Pick the first element (k...
2010-07-28 10:36:45
Quakenet - Snailbot comma...
2010-06-21 21:30:52
Using the MATLAB profiler...
2010-05-31 06:31:14
PHP truncation function
2010-05-06 20:49:26
Quakenet - Fishbot comman...
Paste ID: # mwLQY
Date posted: Wed, 18 Jan 2012 22:26:01 +0000
Date of expiration: never (permanent entry)
Description:

(PHP) Generate / Create (pseudo) random numbers between -1 and 1

  1. <?php
  2. /**To generate (pseudo) random numbers in range of -1 and 1 you can use the cosine
  3.  * that will return a number in range of -1.0 and 1.0.
  4.  *
  5.  * Note for nerds:
  6.  * It's not a real big problem that the cosine is deterministic due to the fact that mt_rand isn't really perfect, too. Hence this is PSEUDO random number generation.
  7.  */
  8. $r = cos( mt_rand() );
  9.  
  10. // In case your mt_rand() implementation returns (for whatever reason) values between 0.0 and 1.0 go with:
  11. $r = cos( mt_rand() );
  12. if( intval( mt_rand() ) % 2 == 0 ) // Switch sign randomly
  13.   $r = -$r;
  14. ?>
You can paste a correction or amendment to the upper paste or a new paste down below.