wordsearch prototype

Author: acharneski

experiments/wordsearch/src/fill/filler.js

@@ -51,6 +51,7 @@ export function* fillGridSteps(grid, model, config = {}) {
     rng = Math.random,
     lattice = 'square',
     includeBackwards = true,
+    reverseModel = null,
   } = config;
   const alphabet = [...model.alphabet];
   let cell;
@@ -63,7 +64,11 @@ export function* fillGridSteps(grid, model, config = {}) {
     for (const d of dirs) {
       const ctx = readContext(grid, x, y, d, model.order, lattice);
       if (ctx) {
-        const dist = model.predict(ctx);
+        // Backward-oriented vectors are best predicted by a model trained on
+        // the reversed stream; their context must be reversed to match.
+        const useReverse = d.forward === false && reverseModel;
+        const queryCtx = useReverse ? [...ctx].reverse().join('') : ctx;
+        const dist = (useReverse ? reverseModel : model).predict(queryCtx);
         if (dist.size) {
           dists.push(dist);
           contexts.push({ dir: d.name, ctx });
@@ -95,6 +100,7 @@ export function fillGrid(grid, model, config = {}) {
     rng = Math.random,
     lattice = 'square',
     includeBackwards = true,
+    reverseModel = null,
   } = config;
   const alphabet = [...model.alphabet];
 
@@ -107,7 +113,10 @@ export function fillGrid(grid, model, config = {}) {
     for (const d of dirs) {
       const ctx = readContext(grid, x, y, d, model.order, lattice);
       if (ctx) {
-        const dist = model.predict(ctx);
+        // Use the reverse-trained model for backward-oriented vectors.
+        const useReverse = d.forward === false && reverseModel;
+        const queryCtx = useReverse ? [...ctx].reverse().join('') : ctx;
+        const dist = (useReverse ? reverseModel : model).predict(queryCtx);
         if (dist.size) dists.push(dist);
       }
     }

experiments/wordsearch/src/generator.js

@@ -30,16 +30,28 @@ export function generatePuzzle(opts) {
     lattice = 'square',
     includeBackwards = true,
     model: providedModel,
+    reverseModel: providedReverseModel,
   } = opts;
 
   const model = providedModel || new MarkovModel(order).train(referenceText, order);
+  // Reverse model only matters when backward-oriented vectors participate.
+  const reverseModel = includeBackwards
+    ? providedReverseModel || new MarkovModel(order).train(referenceText, order, { reverse: true })
+    : null;
 
   const grid = new Grid(width, height);
   const placement = placeWords(grid, words, rng, { lattice, includeBackwards });
-  fillGrid(grid, model, { combiner, sampling, rng, lattice, includeBackwards });
+  fillGrid(grid, model, {
+    combiner,
+    sampling,
+    rng,
+    lattice,
+    includeBackwards,
+    reverseModel,
+  });
   grid.lattice = lattice;
 
-  return { grid, placement, model };
+  return { grid, placement, model, reverseModel };
 }
 /**
  * Build the puzzle scaffold (grid + placed words + trained model) but
@@ -57,9 +69,13 @@ export function preparePuzzle(opts) {
     lattice = 'square',
     includeBackwards = true,
     model: providedModel,
+    reverseModel: providedReverseModel,
   } = opts;
   const model = providedModel || new MarkovModel(order).train(referenceText, order);
+  const reverseModel = includeBackwards
+    ? providedReverseModel || new MarkovModel(order).train(referenceText, order, { reverse: true })
+    : null;
   const grid = new Grid(width, height);
   const placement = placeWords(grid, words, rng, { lattice, includeBackwards });
-  return { grid, placement, model };
+  return { grid, placement, model, reverseModel };
 }

experiments/wordsearch/src/markov/MarkovModel.js

@@ -32,10 +32,14 @@ export class MarkovModel {
    * from 0 (unigram) up to `order`.
    * @param {string} text
    * @param {number} [order]
+   * @param {object} [opts]
+   * @param {boolean} [opts.reverse] train on the reversed character stream
    */
-  train(text, order = this.order) {
+  train(text, order = this.order, opts = {}) {
+    const { reverse = false } = opts;
     this.order = order;
-    const clean = normaliseText(text);
+    let clean = normaliseText(text);
+    if (reverse) clean = [...clean].reverse().join('');
     for (const ch of clean) this.alphabet.add(ch);
 
     for (let i = 0; i < clean.length; i++) {

experiments/wordsearch/src/ui/watchMode.js

@@ -59,10 +59,10 @@ function doStep(root) {
 export function initWatch(root, cfg) {
   clearTimer();
   stepCount = 0;
-  const { grid, model } = preparePuzzle(cfg);
+  const { grid, model, reverseModel } = preparePuzzle(cfg);
   stepGrid = grid;
   stepLattice = cfg.lattice || 'square';
-  stepGen = fillGridSteps(grid, model, cfg);
+  stepGen = fillGridSteps(grid, model, { ...cfg, reverseModel });
   renderState(root, null);
 }