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+      subroutine l2knts ( break, l, k, t, n )
+c  from  * a practical guide to splines *  by c. de boor
+c  to be called in main program  l 2 m a i n .
+converts the breakpoint sequence  b r e a k   into a corresponding knot
+c  sequence  t	to allow the repr. of a pp function of order  k  with
+c  k-2 continuous derivatives as a spline of order  k  with knot
+c  sequence  t . this means that
+c  t(1), ..., t(n+k) =	break(1) k times, then break(i), i=2,...,l, each
+c			once, then break(l+1) k times .
+c  therefore,  n = k-1 + l.
+c
+c******  i n p u t  ******
+c  k	 the order
+c  l	 the number of polynomial pieces
+c  break(1), ...,break(l+1)  the breakpoint sequence
+c
+c******  o u t p u t  ******
+c  t(1),...,t(n+k)   the knot sequence
+c  n	 the dimension of the corresp. spline space of order  k .
+c
+      integer k,l,n,   i,km1
+      real break(1),t(1)
+c     dimension break(l+1),t(n+k)
+      km1 = k - 1
+      do 5 i=1,km1
+    5	 t(i) = break(1)
+      do 6 i=1,l
+    6	 t(km1+i) = break(i)
+      n = km1 + l
+      do 7 i=1,k
+    7	 t(n+i) = break(l+1)
+					return
+      end