fix NaN in radial layout

Author: stuarthalloway

samples/twitterbuzz/src/twitterbuzz/layout.cljs

@@ -45,7 +45,7 @@
   [mentions-data]
   (let [mentions #(rad/get-mentions mentions-data %)
         weights (rad/weights
-                 (into #{} (mapcat mentions (keys mentions-data)))
+                 (into (set (roots mentions-data)) (mapcat mentions (keys mentions-data)))
                  mentions)]
     {:mentions mentions-data
      :locs (-> (rad/layout (roots mentions-data) weights mentions)

samples/twitterbuzz/src/twitterbuzz/radial.cljs

@@ -55,7 +55,8 @@
      (layout nodes weight-fn child-fn 1 0 360 #{}))
   ([nodes weight-fn child-fn radius a1 a2 seen]
      (let [slice (- a2 a1)
-           total-weight (reduce + (map weight-fn nodes))
+           total-weight (reduce + (map #(or (weight-fn %)
+                                            (throw (str "No weight for " %))) nodes))
            seen (into seen nodes)]
        (loop [m {}
               c1 a1