diff --git a/deps.edn b/deps.edn
index 8bad737..c156458 100644
--- a/deps.edn
+++ b/deps.edn
@@ -12,6 +12,11 @@
            :jar {:replace-deps {com.github.seancorfield/depstar {:mvn/version "2.0.193"}}
                  :exec-fn hf.depstar/jar
                  :exec-args {:jar "TightlyPackedTrie.jar" :sync-pom true}}
+           :runner {:extra-deps {com.cognitect/test-runner
+                                 {:git/url "https://github.com/cognitect-labs/test-runner"
+                                  :sha "b6b3193fcc42659d7e46ecd1884a228993441182"}}
+                    :main-opts ["-m" "cognitect.test-runner"
+                                "-d" "test"]}
            :deploy {:replace-deps {slipset/deps-deploy {:mvn/version "0.1.5"}}
                     :exec-fn deps-deploy.deps-deploy/deploy
                     :exec-args {:installer :remote
diff --git a/src/com/owoga/tightly_packed_trie.clj b/src/com/owoga/tightly_packed_trie.clj
index 09706f9..f215f41 100644
--- a/src/com/owoga/tightly_packed_trie.clj
+++ b/src/com/owoga/tightly_packed_trie.clj
@@ -7,6 +7,8 @@
   (:import (java.io ByteArrayOutputStream ByteArrayInputStream
                     DataOutputStream DataInputStream)))
 
+#_(set! *warn-on-reflection* true)
+
 ;; A trie data structure that can be converted to
 ;; a contiguous array of bytes while maintaining
 ;; efficient lookups.
@@ -106,6 +108,7 @@
      :count freq}))
 
 (declare -value)
+(declare children-)
 
 (deftype TightlyPackedTrie [^java.nio.ByteBuffer byte-buffer
                             ^Integer key
@@ -137,28 +140,7 @@
                         value-decode-fn)]
              (trie/lookup child (rest ks))))))))
   (children [self]
-    (wrap-byte-buffer
-     byte-buffer
-     (.limit byte-buffer limit)
-     (.position byte-buffer address)
-     (let [val (value-decode-fn byte-buffer)
-           size-of-index (encoding/decode byte-buffer)]
-       (.limit byte-buffer ^Integer (+ (.position byte-buffer)
-                                       size-of-index))
-       (loop [children []]
-         (if (= (.position byte-buffer) (.limit byte-buffer))
-           children
-           (let [child-key (encoding/decode-number-from-tightly-packed-trie-index byte-buffer)
-                 child-offset (encoding/decode-number-from-tightly-packed-trie-index byte-buffer)]
-             (recur
-              (conj
-               children
-               (TightlyPackedTrie.
-                byte-buffer
-                child-key
-                (- address child-offset)
-                (.capacity byte-buffer)
-                value-decode-fn)))))))))
+    (children- byte-buffer address limit value-decode-fn))
 
   clojure.lang.ILookup
   (valAt [self ks]
@@ -207,6 +189,34 @@
      (.position byte-buffer ^Integer (.address trie))
      (value-decode-fn byte-buffer))))
 
+(defn children- [^java.nio.ByteBuffer
+                 byte-buffer
+                 ^Integer address
+                 ^Integer limit
+                 value-decode-fn]
+  (wrap-byte-buffer
+   byte-buffer
+   (.limit byte-buffer limit)
+   (.position byte-buffer address)
+   (let [val (value-decode-fn byte-buffer)
+         size-of-index (encoding/decode byte-buffer)]
+     (.limit byte-buffer ^Integer (+ (.position byte-buffer)
+                                     size-of-index))
+     (loop [children []]
+       (if (= (.position byte-buffer) (.limit byte-buffer))
+         children
+         (let [child-key (encoding/decode-number-from-tightly-packed-trie-index byte-buffer)
+               child-offset (encoding/decode-number-from-tightly-packed-trie-index byte-buffer)]
+           (recur
+            (conj
+             children
+             (TightlyPackedTrie.
+              byte-buffer
+              child-key
+              (- address child-offset)
+              (.capacity byte-buffer)
+              value-decode-fn)))))))))
+
 (defmethod print-method TightlyPackedTrie [trie ^java.io.Writer w]
   (print-method (into {} trie) w))
 
diff --git a/src/com/owoga/trie.clj b/src/com/owoga/trie.clj
index 40d6467..6d00844 100644
--- a/src/com/owoga/trie.clj
+++ b/src/com/owoga/trie.clj
@@ -253,6 +253,17 @@
     (make-trie)
     (partition 2 ks))))
 
+(defn make-trie'
+  "nil root key instead of empty list, clearer interface"
+  ([]
+   (->Trie nil nil (sorted-map)))
+  ([& ks]
+   (reduce
+    (fn [t kv]
+      (conj t kv))
+    (make-trie)
+    (partition 2 ks))))
+
 (comment
   (make-trie "do" "do" "dot" "dot" "dog" "dog")
   ;; => {[\d \o \g] "dog", [\d \o \t] "dot", [\d \o] "do"}
@@ -282,3 +293,33 @@
        (into (make-trie)))
   ;; => {[1 2 2] 244, [1 2 3] 246, [1 2 4] 248, [1 2] 24}
   )
+
+(defn trie->children-at-depth
+  [[[node & nodes] & stack] [parent & parents] min-depth max-depth]
+  (let [current-depth (count parents)]
+    (cond
+      (and node (< current-depth max-depth))
+      (trie->children-at-depth
+       (into (into stack (list nodes))
+             (list (children node)))
+       (cons node (if parent (cons parent parents) nil))
+       min-depth
+       max-depth)
+      (and parent (some? (get parent [])) (>= current-depth min-depth))
+      (lazy-seq
+       (cons (clojure.lang.MapEntry.
+              (rest (reverse (map #(.key %) (cons parent parents))))
+              (get parent []))
+             (trie->children-at-depth stack (sequence parents) min-depth max-depth)))
+      parent
+      (trie->children-at-depth stack (sequence parents) min-depth max-depth)
+      :else
+      nil)))
+
+(defn children-at-depth
+  ([trie depth]
+   (children-at-depth trie depth (inc depth)))
+  ([trie min-depth max-depth]
+   (trie->children-at-depth
+    `((~trie)) '() min-depth max-depth)))
+
diff --git a/src/com/owoga/trie/math.clj b/src/com/owoga/trie/math.clj
index 4df2792..4ff8e39 100644
--- a/src/com/owoga/trie/math.clj
+++ b/src/com/owoga/trie/math.clj
@@ -27,6 +27,7 @@
       (->Vose N alias prob)
       (let [^doubles ps (->> dist
                              (map (partial * N))
+                             (map float)
                              (into-array Double/TYPE))
 
             [small large] (loop [i 0
@@ -65,7 +66,7 @@
         (->Vose N alias prob)))))
 
 (defn from-weights [ws]
-  (let [tot (reduce + 0.0 ws)]
+  (let [tot (apply + ws)]
     (assert (> tot 0) "Can't Vose RNG from 0 weights.")
     (let [dist (map #(/ % tot) ws)]
       (make-vose (vec dist)))))
diff --git a/test/tightly_packed_trie/core_test.clj b/test/tightly_packed_trie/core_test.clj
deleted file mode 100644
index 3b0d2bc..0000000
--- a/test/tightly_packed_trie/core_test.clj
+++ /dev/null
@@ -1,21 +0,0 @@
-(ns tightly-packed-trie.core-test
-  "Basic tests for the primary API of `next.jdbc`."
-  (:require [clojure.test :refer [deftest is testing use-fixtures]]
-            [com.owoga.tightly-packed-trie.core :as tpt]))
-
-(deftest basic-tests
-  ;; use ds-opts instead of (ds) anywhere you want default options applied:
-  (testing "map-based trie"
-    (let [trie (tpt/trie)]
-      (testing "key not found"
-        (is (thrown-with-msg?
-             Exception
-             #"Key not found"
-             (get trie '("foo"))))
-        (is (= :not-found
-               (get trie '("foo") :not-found))))
-      (testing "conjing to trie"
-        (let [trie (conj trie '("d" "o" "g" "dog"))]
-          (is (instance? com.owoga.tightly_packed_trie.core.Trie (get trie '("d" "o" "g"))))
-          (is (= (tpt/as-map (get trie '("d" "o" "g")))
-                 {"g" {:value "dog" :count 1}})))))))
diff --git a/test/tightly_packed_trie_test.clj b/test/tightly_packed_trie_test.clj
index bad1a05..13a7438 100644
--- a/test/tightly_packed_trie_test.clj
+++ b/test/tightly_packed_trie_test.clj
@@ -81,6 +81,18 @@
                [[]  nil])
              (seq (trie/lookup initialized-trie [1 2])))))))
 
+(deftest children-at-depth-tests
+  (let [initialized-trie (->> (trie/make-trie '(1) 1 '(1 2 3) 123 '(1 2 1) 121 '(1 2 2) 122 '(1 3 1) 131
+                                              '(1 2 3 4) 1234
+                                              '(1 2 3 4 5 6) 123456)
+                              (#(tpt/tightly-packed-trie % value-encode-fn value-decode-fn)))]
+    (testing "children at depth"
+      (is (= '([(1) 1])
+             (trie/children-at-depth initialized-trie 0)))
+      (is (= '([(1 2 3 4 5 6) 123456]
+               [(1 2 3 4) 1234])
+             (trie/children-at-depth initialized-trie 4 6))))))
+
 (comment
   (let [trie (trie/make-trie '(1 2 3) 123 '(1 2 1) 121 '(1 2 2) 122 '(1 3 1) 131)
         tpt (tpt/tightly-packed-trie trie value-encode-fn value-decode-fn)
@@ -94,4 +106,18 @@
       (encode/decode-number-from-tightly-packed-trie-index byte-buffer)
       (encode/decode-number-from-tightly-packed-trie-index byte-buffer)]))
 
+  (let [trie (trie/make-trie '(1) 1 '(1 2) 12 '(1 3) 13 '(2 3) 23 '(5) 5 '(6 7 8) 678)
+        tpt (tpt/tightly-packed-trie trie value-encode-fn value-decode-fn)]
+    (get tpt []))
+
+  (let [trie (trie/make-trie '(1) 1 '(1 2) 12 '(1 3) 13 '(2 3) 23 '(5) 5 '(6 7 8) 678)
+        tpt (tpt/tightly-packed-trie trie value-encode-fn value-decode-fn)]
+    (tpt/trie->children-at-depth (list (list tpt)) '() 3 5))
+
   )
+
+(let [trie (trie/make-trie '(1 2 3) 123 '(1 2 1) 121 '(1 2 2) 122 '(1 3 1) 131)
+      initialized-trie (-> trie
+                            (tpt/tightly-packed-trie value-encode-fn value-decode-fn))]
+  [initialized-trie
+   trie])
diff --git a/test/trie_test.clj b/test/trie_test.clj
index 32b2170..4953bb1 100644
--- a/test/trie_test.clj
+++ b/test/trie_test.clj
@@ -33,3 +33,16 @@
              (seq initialized-trie)))
       (is (= '([[1 2] 12] [[1] 1])
              (seq (assoc initialized-trie '(1) 1)))))))
+
+(deftest children-at-depth-tests
+  (let [initialized-trie (->> (trie/make-trie '(1) 1 '(1 2 3) 123 '(1 2 1) 121 '(1 2 2) 122 '(1 3 1) 131
+                                              '(1 2 3 4) 1234
+                                              '(1 2 3 4 5 6) 123456))]
+    (testing "children at depth"
+      (is (= '([(1) 1])
+             (trie/children-at-depth initialized-trie 0)))
+      (is (= '([(1 2 3 4 5 6) 123456]
+               [(1 2 3 4) 1234])
+             (trie/children-at-depth initialized-trie 4 6)))
+      (is (= nil (trie/children-at-depth initialized-trie -1)))
+      (is (= nil (trie/children-at-depth initialized-trie 5 4))))))