Data update

Task/Entropy/AutoLISP/entropy.l

@@ -0,0 +1,40 @@
+(defun entropy (str / log2 eCalc strList len ent cnt n new end cPrev)
+  (defun log2 (x)
+    (if (> x 0)
+      (/ (log x) (log 2.0))
+    )
+  )
+  (defun eCalc (cnt len / p)
+    (setq p (/ (float cnt) len))
+    (* p (log2 p))
+  )
+  (setq
+    strList (acad_strlsort (mapcar 'chr (vl-string->list str)))
+    len (length strList)
+    ent 0.0
+    cnt 0
+    n 0
+  )
+  (foreach c strList
+    (setq
+      n (1+ n)
+      new (and cPrev (not (eq c cPrev)))
+      end (= n len)
+    )
+    (if (or new end)
+      (setq
+        cnt (if (and end (not new)) (1+ cnt) cnt)
+        ent (+ ent (eCalc cnt len))
+        cnt 0
+      )
+    )
+    (if (and new end)
+      (setq ent (+ ent (eCalc 1 len)))
+    )
+    (setq
+      cnt (1+ cnt)
+      cPrev c
+    )
+  )
+  (* -1 ent)
+)

Task/Entropy/DuckDB/entropy.duckdb

@@ -0,0 +1,16 @@
+# h should be a DuckDB histogram and n should be map_values(h).list_sum()
+create or replace function h2e(h, n) as (
+  - map_values(h).list_transform( x -> x * log2(x/n)).list_sum() / n
+);
+
+# str is normally a string but if not, will be cast to one
+create or replace function shannon_entropy(str) as (
+  with cte as (
+    from unnest( string_split(str::VARCHAR,'')) _(s)
+  ),
+  n as (select count(*) as n from cte),
+  h as (select histogram(s) as h from cte)
+  select h2e(h,n) from h, n
+);
+
+select shannon_entropy(1223334444);

Task/Entropy/Elena/entropy.elena

@@ -38,5 +38,5 @@ public program()
 
     infoC *= -1;
 
-    console.printLine("The Entropy of ", input, " is ", infoC)
+    Console.printLine("The Entropy of ", input, " is ", infoC)
 }