Data update

Task/Arithmetic-derivative/XPL0/arithmetic-derivative.xpl0

@@ -0,0 +1,28 @@
+function integer Lagarias (N); \Lagarias arithmetic derivative
+integer N;
+integer F, Q;
+
+        function integer SmallPF (J, K); \Smallest prime factor
+        integer J, K;
+        return if rem(J/K) = 0 then K else SmallPF(J, K+1);
+
+begin
+if N < 0
+then return -Lagarias (-N)
+else if N = 0 or N = 1
+then return 0
+else    begin
+        F := SmallPF (N, 2);  Q := N / F;
+        return if Q = 1
+        then 1
+        else Q * Lagarias (F)  +  F * Lagarias (Q)
+        end;
+end \Lagarias\ ;
+
+integer N;
+begin
+    for N:= -99 to 100 do begin
+        IntOut(0, Lagarias(N) );
+        if rem(N/10) = 0 then CrLf(0) else ChOut(0, 9\tab\);
+    end;
+end