MOAR WHITESPACE

Author: CodeFarmer

src/decision_tree/core.clj

@@ -1,8 +1,13 @@
 (ns decision-tree.core)
 
+
 (defn log2 [x]
+
+  "Return the base-2 logarithm of x"
+
   (/ (Math/log x) (Math/log 2)))
 
+
 (defn entropy [alist]
 
   "Given a list of pairs if (input, output), calculate the entropy of the list with respect to output"
@@ -32,13 +37,16 @@
            (recur
             (assoc acc o [i]) afn (rest aseq)))))))
 
+
 (defn all-keys [aseq]
 
   "Given a list of maps, return a set containing all the keys from those maps"
 
   (into #{} (flatten (map keys aseq))))
 
+
 (defn gain
+
   ([k alist]
 
      "Given a key and a list of pairs of (map, output), return the net reduction in entropy caused by partitioning the list according to the values associated with key in the input maps"
@@ -51,6 +59,9 @@
           (reduce +
            (map #(* (entropy %) (/ (count %) (count alist))) parts))))))
 
+
 (defn most-informative-key [aseq]
+
   "Given a sequence of pairs of (map, output), return the map key that provides the highest information gain about outout, when used to partition the sequence"
+
   (apply max-key #(gain % aseq) (all-keys (map first aseq))))