*
* $Id: lorenb.F,v 1.1.1.1 1996/02/15 17:49:49 mclareni Exp $
*
* $Log: lorenb.F,v $
* Revision 1.1.1.1  1996/02/15 17:49:49  mclareni
* Kernlib
*
*
#include "kerngen/pilot.h"
      SUBROUTINE LORENB (U,PS,PI,PF)
C
C CERN PROGLIB# U102    LORENB          .VERSION KERNFOR  4.04  821124
C ORIG. 20/08/75 L.PAPE
C
#if !defined(CERNLIB_B48M)
      DOUBLE PRECISION PF4, FN
#endif
      DIMENSION      PS(4),PI(4),PF(4)

      IF (PS(4).EQ.U) GO TO 17
      PF4  = (PI(4)*PS(4)+PI(3)*PS(3)+PI(2)*PS(2)+PI(1)*PS(1)) / U
      FN   = (PF4+PI(4)) / (PS(4)+U)
      PF(1)= PI(1) + FN*PS(1)
      PF(2)= PI(2) + FN*PS(2)
      PF(3)= PI(3) + FN*PS(3)
      PF(4)= PF4
      GO TO 18
C
   17 PF(1)= PI(1)
      PF(2)= PI(2)
      PF(3)= PI(3)
      PF(4)= PI(4)
C
   18 CONTINUE
C
      RETURN
C
      END