note 53784 added to function.rand

Random numbers with Gauss distribution (normal distribution). A correct alghoritm. Without aproximations, like Smaaps' It is specially usefull for simulations in physics. Check yourself, and have a fun. <?php function gauss() { // N(0,1) // returns random number with normal distribution: // mean=0 // std dev=1 // auxilary vars $x=random_0_1(); $y=random_0_1(); // two independent variables with normal distribution N(0,1) $u=sqrt(-2*log($x))*cos(2*pi()*$y); $v=sqrt(-2*log($x))*sin(2*pi()*$y); // i will return only one, couse only one needed return $u; } function gauss_ms($m=0.0,$s=1.0) { // N(m,s) // returns random number with normal distribution: // mean=m // std dev=s return gauss()*$s+$m; } function random_0_1() { // auxiliary function // returns random number with flat distribution from 0 to 1 return (float)rand()/(float)getrandmax(); } ?> JanS student of astronomy on Warsaw University ---- Manual Page -- http://www.php.net/manual/en/function.rand.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+53784 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+53784&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+53784&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+53784&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+53784&report=yes&reason=useless Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+53784&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+53784&report=yes Search -- http://master.php.net/manage/user-notes.php