Fix AdagradOptimizer bug (#183)

* Update session_test.ts

* Update adagrad_optimizer.ts

* Update adagrad_optimizer.ts

* Update model-builder.ts

Author: SayHelloToWorld

demos/model-builder/model-builder.ts

@@ -369,7 +369,6 @@ export class ModelBuilder extends ModelBuilderPolymer {
         break;
       }
       case "adagrad": {
-        this.needMomentum = true;
         break;
       }
       default: {
@@ -390,7 +389,7 @@ export class ModelBuilder extends ModelBuilderPolymer {
         return new RMSPropOptimizer(+this.learningRate, +this.gamma);
       }
       case 'adagrad': {
-        return new AdagradOptimizer(+this.learningRate, +this.momentum);
+        return new AdagradOptimizer(+this.learningRate);
       }
       default: {
         throw new Error(`Unknown optimizer "${this.selectedOptimizerName}"`);

src/graph/optimizers/adagrad_optimizer.ts

@@ -24,10 +24,8 @@ import {Optimizer} from './optimizer';
 
 export class AdagradOptimizer extends Optimizer {
   constructor(
-      protected learningRate: number, protected momentum: number,
-      specifiedVariableList?: Node[]) {
+      protected learningRate: number, specifiedVariableList?: Node[]) {
     super(learningRate, specifiedVariableList);
-    this.m = Scalar.new(momentum);
     this.eps = Scalar.new(1e-6);
   }
 
@@ -74,12 +72,10 @@ export class AdagradOptimizer extends Optimizer {
 
   dispose() {
     super.dispose();
-    this.m.dispose();
     this.eps.dispose();
     this.accumulatedSquaredGradients.dispose();
   }
 
   private accumulatedSquaredGradients = new TensorArrayMap();
-  private m: Scalar;
   private eps: Scalar;
 }

src/graph/session_test.ts

@@ -354,7 +354,7 @@ describe('Session', () => {
     const y = g.reduceSum(g.add(g.matmul(w, x), b));
 
     const safeMode = true;
-    const optimizer = new AdagradOptimizer(0.1, 0.5);
+    const optimizer = new AdagradOptimizer(0.1);
     const math = new NDArrayMathCPU(safeMode);
     const session = new Session(g, math);
     const inputProvider: InputProvider = {