Data commit

Task/Knuths-power-tree/EchoLisp/knuths-power-tree-1.l

@@ -0,0 +1,40 @@
+(lib 'tree)
+
+;; displays a chain hit
+(define (power-hit target chain)
+	(vector-push chain target)
+	(printf "L(%d) = %d - chain:%a "
+		target (1- (vector-length chain)) chain)
+	(vector-pop chain))
+	
+;; build the power-tree : add 1 level of leaf nodes
+;; display all chains which lead to target
+
+(define (add-level node chain  target  nums (new))
+(vector-push chain (node-datum node))
+	(cond
+	[(node-leaf? node)
+	;; add leaves by summing this node to all nodes in chain
+	;; do not add leaf if number already known
+			 (for [(prev chain)]
+			 		(set! new (+ prev (node-datum node)))
+			 		(when (= new target) (power-hit target chain ))
+			 		#:continue (vector-search* new nums)
+			 		(node-add-leaf node new)
+			 		(vector-insert* nums new)
+			 		)]
+	[else ;; not leaf node -> recurse
+	(for [(son  (node-sons node))]
+		(add-level son chain target nums )) ])
+	(vector-pop chain))
+	
+;; add levels in tree until target found
+;; return (number of nodes . upper-bound for L(target))
+(define (power-tree target)
+	(define nums (make-vector 1 1)) ;; known nums =  1
+	(define T (make-tree 1)) ;; root node has value 1
+	(printf "Looking for %d in %a." target T)
+	(while #t
+	#:break (vector-search* target nums) =>  (tree-count T)
+	(add-level T init-chain: (make-vector 0) target  nums)
+	))

Task/Knuths-power-tree/EchoLisp/knuths-power-tree-2.l

@@ -0,0 +1,11 @@
+;; j such  as chain[i] = chain[i-1] + chain[j]
+(define (adder chain  i)
+	(for ((j i)) #:break (= [chain i] (+ [chain(1-  i)] [chain j])) => j ))
+		
+		
+(define (power-exp x chain)
+	(define lg (vector-length chain))
+	(define pow (make-vector lg x))
+	(for ((i  (in-range 1 lg)))
+	(vector-set! pow  i ( * [pow [1- i]] [pow (adder chain i)])))
+	[pow (1- lg)])