Use ADADELTA for MNIST example.

h2o-samples/src/main/java/samples/expert/DeepLearningMnist.java

@@ -41,19 +41,27 @@ public static void main(String[] args) throws Exception {
     p.seed = seed;
     p.hidden = new int[]{1024,1024,2048};
 //    p.hidden = new int[]{128,128,256};
-    p.rate = 0.01;
-    p.rate_annealing = 1e-6;
     p.activation = DeepLearning.Activation.RectifierWithDropout;
     p.loss = DeepLearning.Loss.CrossEntropy;
     p.input_dropout_ratio = 0.2;
     p.max_w2 = 15;
     p.epochs = 10000;
     p.l1 = 1e-5;
     p.l2 = 0;
-    p.adaptive_rate = false;
-    p.momentum_start = 0.5;
-    p.momentum_ramp = 1800000;
-    p.momentum_stable = 0.99;
+
+    // automatic learning rate
+    p.adaptive_rate = true;
+    p.rho = 0.99;
+    p.epsilon = 1e-8;
+
+    // manual learning rate
+//    p.adaptive_rate = false;
+//    p.rate = 0.01;
+//    p.rate_annealing = 1e-6;
+//    p.momentum_start = 0.5;
+//    p.momentum_ramp = 1800000;
+//    p.momentum_stable = 0.99;
+
     p.initial_weight_distribution = DeepLearning.InitialWeightDistribution.UniformAdaptive;
 //    p.initial_weight_scale = 0.01
     p.classification = true;