Data commit

Task/Digital-root/Picat/digital-root.picat

@@ -0,0 +1,18 @@
+go =>
+  foreach(N in [627615,39390,588225,393900588225,
+                58142718981673030403681039458302204471300738980834668522257090844071443085937])
+    [Sum,Persistence] = digital_root(N),
+    printf("%w har addititive persistence %d and digital root of %d\n", N,Persistence,Sum)
+  end,
+  nl.
+
+%
+% (Reduced) digit sum (digital root) of a number
+%
+digital_root(N) = [Sum,Persistence], integer(N)  =>
+   Sum = N,
+   Persistence = 0,
+   while(Sum > 9)
+     Sum := sum([I.to_integer() : I in Sum.to_string()]),
+     Persistence := Persistence + 1
+   end.