add radix tree benchmark

benchmarks/rbtree_bench.js

@@ -1,7 +1,8 @@
 import createTree from "functional-red-black-tree";
+import { emptyTrie, insert } from "../lib/util/trie.js";
 
 function benchmark(N) {
-  // fastest
+  // in-place update of native Map: fastest
   function map() {
     let t = new Map();
     const startTime = Date.now();
@@ -11,10 +12,10 @@ function benchmark(N) {
     const endTime = Date.now();
     return endTime - startTime;
   }
-  const durInPlace = map();
+  const durInPlace = (N <= 5000000) ? map() : "(skip)";
   console.log("in-place:", durInPlace, "ms");
 
-  // slower by constant factor
+  // purely functional red-black tree: slower by constant factor
   function fun() {
     let t = createTree();
     const startTime = Date.now(); 
@@ -25,25 +26,55 @@ function benchmark(N) {
     return endTime - startTime;
   }
   const durFunc = fun();
-  console.log("functional:", durFunc, "ms");
+  console.log("functional red-black:", durFunc, "ms");
 
-  // a bit slower still
+  // purely functional red-black tree (no garbage collection): a bit slower still
   function funNoGC() {
-    const old = new Array(N);
+    const trees = new Array(N);
     let t = createTree();
     const startTime = Date.now(); 
     for (let i=0; i<N; ++i) {
-      old[i] = t; // prevent garbage collection
+      trees[i] = t; // prevent garbage collection
       t = t.insert(Math.random(), Math.random());
     }
     const endTime = Date.now();
     return endTime - startTime;
     
   }
-  const durFuncNoGC = (N <= 1000000) ? funNoGC() : "";
+  const durFuncNoGC = (N <= 1000000) ? funNoGC() : "(skip)";
-  console.log("functional (no GC):", durFuncNoGC, "ms");
+  console.log("functional red-black (no GC):", durFuncNoGC, "ms");
 
-  // slowest (won't scale)
+  // purely functional radix tree
+  function trie() {
+    let t = emptyTrie;
+    const startTime = Date.now(); 
+    for (let i=0; i<N; ++i) {
+      // of course we can only insert strings into radix tree:
+      t = insert(t)(String(Math.random()*10))(Math.random());
+    }
+    const endTime = Date.now();
+    return endTime - startTime;
+  }
+  const durTrie = trie();
+  console.log("functional radix trie:", durTrie, "ms");
+
+  // purely functional radix tree (no garbage collection)
+  function trieNoGC() {
+    const trees = new Array(N);
+    let t = emptyTrie;
+    const startTime = Date.now(); 
+    for (let i=0; i<N; ++i) {
+      trees[i] = t; // prevent garbage collection
+      // of course we can only insert strings into radix tree:
+      t = insert(t)(String(Math.random()*10))(Math.random());
+    }
+    const endTime = Date.now();
+    return endTime - startTime;
+  }
+  const durTrieNoGC = (N <= 1000000) ? trieNoGC() : "(skip)";
+  console.log("functional radix trie (no GC):", durTrieNoGC, "ms");
+
+  // defensive copy of native Map: slowest (won't scale)
   function copying() {
     let t = new Map();
     const startTime = Date.now();
@@ -54,35 +85,44 @@ function benchmark(N) {
     const endTime = Date.now();
     return endTime - startTime;
   }
-  const durCopying = (N <= 50000) ? copying() : "";
+  const durCopying = (N <= 10000) ? copying() : "(skip)";
   console.log("copying:", durCopying, "ms");
 
-  // slower than slowest
+  // defensive copy of native Map (no garbage collection): slower than slowest
   function copyingNoGC() {
-    const old = new Array(N);
+    const maps = new Array(N);
     let t = new Map();
     const startTime = Date.now();
     for (let i=0; i<N; ++i) {
-      old[i] = t; // prevent garbage collection
+      maps[i] = t; // prevent garbage collection
       t = new Map(t);
       t.set(Math.random(), Math.random());
     }
     const endTime = Date.now();
     return endTime - startTime;
   }
-  const durCopyingNoGC = (N <= 10000) ? copyingNoGC() : "";
+  const durCopyingNoGC = (N <= 10000) ? copyingNoGC() : "(skip)";
   console.log("copying (no GC):", durCopyingNoGC, "ms");
 
-  return [N, durInPlace, durFunc, durFuncNoGC, durCopying, durCopyingNoGC];
+  return [N, durInPlace, durFunc, durFuncNoGC, durTrie, durTrieNoGC, durCopying, durCopyingNoGC];
 }
 
+const startTime = Date.now();
+
 const results = [];
-for (const N of [100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, 100000, 200000, 500000, 1000000, 2000000, 5000000, 10000000]) {
+const datapoints = [100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, 100000, 200000, 500000, 1000000, 2000000];
-  console.log("N =", N);
+
+for (let i=0; i<datapoints.length; i++) {
+  const N = datapoints[i];
+  console.log("N =", N, `(run ${i+1}/${datapoints.length})`);
   results.push(benchmark(N));
 }
 
-console.log("N;in-place;functional;functional-NoGC;copying;copying-NoGC");
+const endTime = Date.now();
-for (const [N, durInPlace, durFunc, durFuncNoGC, durCopying, durCopyingNoGC] of results) {
+
-  console.log(`${N};${durInPlace};${durFunc};${durFuncNoGC};${durCopying};${durCopyingNoGC}`);
+console.log("Benchmark took", endTime-startTime, "ms");
+
+console.log("N;in-place;pure-redblack;pure-redblack-NoGC;pure-radix;pure-radix-NoGC;copying;copying-NoGC");
+for (const [N, ...rest] of results) {
+  console.log(`${N};${rest.join(';')}`);
 }

lib/util/trie.js

@@ -1,5 +1,5 @@
-// A purely functional Trie
+// A purely functional Radix Trie
-// https://en.wikipedia.org/wiki/Trie
+// https://en.wikipedia.org/wiki/Radix_tree
 
 
 export const emptyTrie = {