gpamela/gptrd/npoiss.F

*
* $Id: npoiss.F,v 3.1.1.1 2002/07/11 16:02:01 cafagna Exp $
*
* $Log: npoiss.F,v $
* Revision 3.1.1.1  2002/07/11 16:02:01  cafagna
* First GPAMELA release on CVS
*
*
*CMZ :  3.00/00 06/04/2001  11.21.19  by  Marialuigia Ambriola
*-- Author :    Marialuigia Ambriola   05/04/2001
      INTEGER FUNCTION NPOISS(X)
**************************************
* Simulate the Poisson distribution
* From data particle book vol. 15 2000
**************************************
      REAL U(1),A,X
      INTEGER K,N
      NPOISS=0
      K=1
      A=1.
c ml26/03/04 100  U=RNDM(1)
 100  CALL GRNDM(U,1)
      A=U(1)*A
      IF(A.LT.EXP(-X)) THEN
         N=K-1
      ELSE
         K=K+1
         GOTO 100
      ENDIF
      NPOISS=N
      RETURN
      END
1	*
2	* $Id: npoiss.F,v 3.1.1.1 2002/07/11 16:02:01 cafagna Exp $
3	*
4	* $Log: npoiss.F,v $
5	* Revision 3.1.1.1 2002/07/11 16:02:01 cafagna
6	* First GPAMELA release on CVS
7	*
8	*
9	*CMZ : 3.00/00 06/04/2001 11.21.19 by Marialuigia Ambriola
10	*-- Author : Marialuigia Ambriola 05/04/2001
11	INTEGER FUNCTION NPOISS(X)
12	**************************************
13	* Simulate the Poisson distribution
14	* From data particle book vol. 15 2000
15	**************************************
16	REAL U(1),A,X
17	INTEGER K,N
18	NPOISS=0
19	K=1
20	A=1.
21	c ml26/03/04 100 U=RNDM(1)
22	100 CALL GRNDM(U,1)
23	A=U(1)*A
24	IF(A.LT.EXP(-X)) THEN
25	N=K-1
26	ELSE
27	K=K+1
28	GOTO 100
29	ENDIF
30	NPOISS=N
31	RETURN
32	END