real function distobs(a,b,iobsloc,mobs,n)

	implicit none
	integer, intent(in) ::  mobs, n
	integer,   intent(in)  :: iobsloc(mobs) 
	real*8, intent(in) ::   a(mobs), b(n)
	integer i,j

	distobs=(a(1)-b(iobsloc(1)))**2
	do i=2,mobs
	   j = iobsloc(i)
	 distobs=distobs+(a(i)-b(j))**2
c         write (*,*) j, a(i), b(j)
	enddo
	distobs=sqrt(distobs)
	
	return
	end