subroutine pvoldp
c        calculate the volume occupied by a typical superparticle
c-----------------------------------------------------------------------
      include 'param_sz.h'
      include 'coordcom.h'
      include 'ncordscom.h'
      include 'psizescom.h'
      include 'ucom.h'
c
      double precision xp,x,y,z,xav,yav,zav,xavsq,yavsq,zavsq,ag
      integer*4 i
c--------------------------------------------------------------------------
c*
c
      xp = float(ngood)**.666667
      if (ngood.lt.8) return
      xav = 0.
      yav = 0.
      zav = 0.
      xavsq = 0.
      yavsq = 0.
      zavsq = 0.
      do 100 i = 1,ngood
      x = cord(1,i)
      y = cord(3,i)
      z = cord(5,i)
      xav = xav + x
      xavsq = xavsq + x*x
      yav = yav + y
      yavsq = yavsq + y*y
      zav = zav + z
      zavsq = zavsq + z*z
  100 continue
      ag = ngood
      xsqsiz =pvfac*(xavsq/ag - (xav/ag)**2)/xp
      ysqsiz =pvfac*(yavsq/ag - (yav/ag)**2)/xp
      zsqsiz =pvfac*(zavsq/ag - (zav/ag)**2)/xp
      if(xsqsiz*ysqsiz*zsqsiz.le.0.) then
        write(ndiag,*) ' element part ref ',cord(7,1),' volume negatif'
        return
      endif
      xyzvol = dsqrt(xsqsiz*ysqsiz*zsqsiz)
      return
      end
c++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*