Re: Random Number

From: Dmitry G. Zolin <zdg_at_lab321.ru>
Date: 1997/09/29
Message-ID: <01bcccd6$c2f90aa0$5e21e2c2@zdg.l321.omsk.net.ru>#1/1

A re-post:
From: rseligma_at_oracle.com (Russ Seligman) Newsgroups: comp.databases.oracle
Subject: Re: PL/SQL Random Number Generator Date: 01 Nov 1995 19:37:48 GMT
Organization: Oracle Corporation, Redwood Shores, CA

I saw that someone else had posted the PL/SQL code that they had typed in. Here's the code as I originally created it (and presumably as Oracle support
is distributing it)...

--Russ

-----Begin Package Spec-----

package random is
/* Linear congruential random number generator */

/* Returns random integer between [0, r-1] */
function rndint(r in number) return number;

/* Returns random real between [0, 1] */
function rndflt return number;

end; /* package random */

-----End Package Spec-----

-----Begin Package Body-----

package body random is
/* Linear congruential random number generator */

m constant number:=100000000;  /* initial conditions */
m1 constant number:=10000;     /* (for best results) */
b constant number:=31415821;   /*                    */

a number;                      /* seed */

the_date date;                 /*                             */
days number;                   /* for generating initial seed */
secs number;                   /*                             */

/*-------------------------- mult ---------------------------*/

/* Private utility function */

function mult(p in number, q in number) return number is

   p1 number;
   p0 number;
   q1 number;
   q0 number;

begin

   p1:=trunc(p/m1);
   p0:=mod(p,m1);
   q1:=trunc(q/m1);
   q0:=mod(q,m1);

   return(mod((mod(p0*q1+p1*q0,m1)*m1+p0*q0),m)); end; /* mult */

/*-------------------------- rndint --------------------------*/

/* Returns random integer between [0, r-1] */

function rndint (r in number) return number is begin

   /* generate a random number and set it to be the new seed */    a:=mod(mult(a,b)+1,m);

   /* convert it to integer between [0, r-1] and return it */    return(trunc((trunc(a/m1)*r)/m1));
end; /* rndint */

/*-------------------------- rndflt --------------------------*/

/* Returns random real between [0, 1] */

function rndflt return number is
begin

   /* generate a random number and set it to be the new seed */    a:=mod(mult(a,b)+1,m);

   /* return it */
   return(a/m);
end; /* rndflt */

begin /* package body random */

   /* Generate an initial seed "a" based on system date */

   /* (Must be connected to database.)                  */

   the_date:=sysdate;
   days:=to_number(to_char(the_date, 'J'));    secs:=to_number(to_char(the_date, 'SSSSS'));    a:=days*24*3600+secs;
end; /* package body random */

-----End Package Body-----

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  Lee Levy, ISSD Technical Dream Team, Del Code (34)   BHP Information Technology, ACN 006 476 213   PO Box 261, Warrawong, NSW 2502, Australia   PH: +61 42 75-5485 Fax: -5500 Tie: 8855-   Internet : levy.lee.ls_at_bhp.com.au

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Opinions expressed are mostly my own, so give me some credit. Received on Mon Sep 29 1997 - 00:00:00 CDT