subroutine lininv(t,x,y,n)
c
c***	Solves the linear system C*x=y, where C is a matrix with elements
c***
c***		C(i,j)=abs(t(i)-t(j)),  i,j=1,...,n
c***
c***	Here the array t(i) is assumed to be sorted in ascending order,
c***
c***		t(1) < t(2) < ..... < t(n)
c***
c***	A modification of the fast method of Rybicki and Press (1995, 
c***	Phys. Rev. Lett., 74, 1060-1063) is used.
c***
c***	G. Rybicki, 4 March 1998
c
	INTEGER i,j,n,n1,NDIM
	PARAMETER (NDIM=100)
	REAL t(*),x(*),y(*)
	REAL e(NDIM),d(NDIM),corner,HALF
	PARAMETER (HALF=0.5)
c
	if(NDIM.lt.n)then
		stop 'lininv: NDIM too small'
	endif
	n1=n-1
c
	do i=1,n1
		e(i)=HALF/(t(i+1)-t(i))
	enddo
c
	corner=HALF/(t(n)-t(1))
	d(1)=corner-e(1)
	do i=2,n1
		d(i)=-e(i-1)-e(i)
	enddo
	d(n)=corner-e(n1)
c
	x(1)=d(1)*y(1)+e(1)*y(2)+corner*y(n)
	do i=2,n1
		x(i)=e(i-1)*y(i-1)+d(i)*y(i)+e(i)*y(i+1)
	enddo
	x(n)=corner*y(1)+e(n1)*y(n1)+d(n)*y(n)
	return
	end