N=
      SW=0.0
      SWX=0.0
      SWY=0.0
      SWZ=0.0
      VARW=0.0
      VARX=0.0
      VARY=0.0
      VARZ=0.0
      IDUM=
      SS=0.2*(EXP(5.0)-EXP(-5.0))
      VOL=3.0*7.0*SS
      FOR J=1 TO N
          X=1.0+3.0*RAN2(IDUM)
          Y=-3.0+7.0*RAN2(IDUM)
          S=0.00135+SS*RAN2(IDUM)
          Z=0.2*LOG(5.0*S)
          IF Z^2+(SQR(X^2+Y^2)-3.0)^2 < 1.0 THEN
              SW=SW+1.
              SWX=SWX+X
              SWY=SWY+Y
              SWZ=SWZ+Z
              VARW=VARW+1.
              VARX=VARX+X^2
              VARY=VARY+Y^2
              VARZ=VARZ+Z^2
          END IF
           NEXT J
      W=VOL*SW/N
      X=VOL*SWX/N
      Y=VOL*SWY/N
      Z=VOL*SWZ/N
      DW=VOL*SQR((VARW/N-(SW/N)^2)/N)
      DX=VOL*SQR((VARX/N-(SWX/N)^2)/N)
      DY=VOL*SQR((VARY/N-(SWY/N)^2)/N)
      DZ=VOL*SQR((VARZ/N-(SWZ/N)^2)/N)