Updated comments and Readme.md.

Added test2.js for random seed check.

Readme.md

@@ -106,6 +106,15 @@ exports.stop_words = [
 ];
 ```
 
+## Setting a Random Seed
+
+A specific random seed can be used to compute the same terms and probabilities during subsequent runs. You can specify the random seed, as follows:
+
+```javascript
+// Use the random seed 123.
+result = lda(documents, 2, 5, null, null, null, 123);
+```
+
 ## Author
 
 Kory Becker

lib/lda.js

@@ -276,12 +276,12 @@ var lda = new function() {
     }
 
     this.getRandom = function() {
-        // generage a pseudo-random number using a seed to ensure reproducable results.
         if (this.RANDOM_SEED) {
+            // generate a pseudo-random number using a seed to ensure reproducable results.
             var x = Math.sin(this.RANDOM_SEED++) * 1000000;
             return x - Math.floor(x);
-        // use standard random algorithm.
         } else {
+            // use standard random algorithm.
             return Math.random();
         }
     }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "lda",
-  "version": "0.1.7",
+  "version": "0.1.8",
   "description": "LDA topic modeling for node.js.",
   "author": {
     "name": "Kory Becker",
@@ -42,6 +42,6 @@
 	"document",
 	"words"
   ],
-  "_id": "lda@0.1.7",
+  "_id": "lda@0.1.8",
   "_from": "lda"
 }

test2.js

@@ -0,0 +1,52 @@
+var lda = require('./lib/lda');
+
+var text = 'Cats are small. Dogs are big. Cats like to chase mice. Dogs like to eat bones.';
+var documents = text.match( /[^\.!\?]+[\.!\?]+/g );
+var seed = 123;
+
+// Test using random seed for reproducible results.
+var isOk = true;
+var results = [];
+for (var i = 0; i < 10; i++) {
+    results.push(lda(documents, 3, 6, null, null, null, 123));
+}
+
+// Compare each result in the set to ensure matching terms and probability values.
+for (var i in results) {
+    var result = results[i];
+
+    for (var j in result) {
+        var row1 = result[j];
+
+        for (var k in row1) {
+            var term1 = row1[k];
+
+            // Compare this term1 to the term1 in all other results.
+            for (var l in results) {
+                var result2 = results[l];
+
+                // Take same index row as first result.
+                var row2 = result2[j];
+                var term2 = row2[k];
+
+                //console.log(term1.term + ' (' + term1.probability + ') ' + term2.term + ' (' + term2.probability + ')'); 
+
+                if (term1.term != term2.term || term1.probability != term2.probability) {
+                    console.log('Failed match! Term ' + term1.term + ' (' + term1.probability + ') != ' + term2.term + ' (' + term2.probability + ')');
+                    isOk = false;
+                }
+            }
+        }
+    }
+}
+
+if ((results[0][0][0].probability != 0.18 || results[0][0][1].probability != 0.15 || results[0][0][2].probability != 0.12) ||
+    (results[0][1][0].probability != 0.2 || results[0][1][1].probability != 0.15 || results[0][1][2].probability != 0.12))
+{
+    console.log('Failed expected values for random seed ' + seed + '.')
+    isOk = false;
+}
+
+if (isOk) {
+    console.log('\nRandom seed (' + seed + ') OK.');
+}