Merge pull request #279 from longouyang/early-enumeration-exit

Enumeration: exit early if we fail to satisfy a hard factor

src/inference/enumerate.js

@@ -91,6 +91,9 @@ module.exports = function(env) {
   Enumerate.prototype.factor = function(s, cc, a, score) {
     // Update score and continue
     this.score += score;
+    if (this.score === -Infinity) {
+      return this.exit();
+    }
     return cc(s);
   };
 

tests/test-data/stochastic/expected/earlyExit.json

@@ -0,0 +1,5 @@
+{
+  "hist": {
+    "30": 1
+  }
+}

tests/test-data/stochastic/models/earlyExit.wppl

@@ -0,0 +1,11 @@
+var model = function() {
+  var i = randomInteger(10);
+  factor(i === 5 ? 0 : -Infinity)
+  assert.ok(i === 5);
+
+  var j = randomInteger(12);
+  factor(j === 6 ? 0 : -Infinity)
+  assert.ok(j === 6);
+
+  return i * j;
+};

tests/test-inference.js

@@ -50,7 +50,8 @@ var tests = [
       geometric: { args: [10] },
       cache: true,
       withCaching: true,
-      optionalErpParams: true
+      optionalErpParams: true,
+      earlyExit: true
     }
   },
   {