Expose Adam in BS

Source/Math/GPUMatrix.cu

@@ -1537,10 +1537,10 @@ void GPUMatrix<ElemType>::FSAdagrad(GPUMatrix<ElemType>& gradients,
 template <class ElemType>
 void GPUMatrix<ElemType>::Adam(GPUMatrix<ElemType>& gradients,
     GPUMatrix<ElemType>& functionValues,
-    ElemType learnRatePerSample,
-    ElemType momentum,
-    ElemType adaWeight,
-    ElemType adaMul,
+    ElemType learnRatePerSample, //alpha
+    ElemType momentum, // /beta_1 
+    ElemType adaWeight, // /beta_2
+    ElemType adaMul, //biasCorrection
     ElemType epsilon,
     ElemType unitGainFactor,
     bool adamax)

Source/Math/Matrix.cpp

@@ -1828,6 +1828,10 @@ void Matrix<ElemType>::FSAdagradUpdate(Matrix<ElemType>& gradients, Matrix<ElemT
 // Implement the original adam algorithm according to the paper
 // Ref: ADAM: A METHOD FOR STOCHASTIC OPTIMIZATION, https://arxiv.org/pdf/1412.6980.pdf
 /// 
+// Association between the method parameters and the paper notation:
+// smoothedCount - t 
+// meanMomentum - /beta_1 
+// varMomentum - /beta_2
 template <class ElemType>
 void Matrix<ElemType>::AdamUpdate(Matrix<ElemType>& gradients, Matrix<ElemType>& functionValues, const double smoothedCount,
     const double learnRatePerSample, const double meanMomentum, const double varMomentum, const double epsilon, ElemType unitGainFactor, bool adamax)

Source/SGDLib/SGD.cpp

@@ -2429,6 +2429,11 @@ void SGD<ElemType>::UpdateWeights(Matrix<ElemType>& functionValues, Matrix<ElemT
                                                         (ElemType) m_rpi.dec, (ElemType) m_rpi.min, needAveMultiplier, true);
         Matrix<ElemType>::ScaleAndAdd((ElemType)(-learnRatePerSample / aveMultiplier), gradientValues, functionValues);
     }
+    else if (adpType == GradientsUpdateType::Adam)
+    {
+        smoothedGradientValues.AdamUpdate(gradientValues, functionValues, smoothedCount + 1, learnRatePerSample,
+            m_adam.meanMomentum, m_adam.varMomentum, m_adam.epsilon, (ElemType)(1 - m_adam.meanMomentum), false);
+    }
 
     if (noiseStd > 0)
     {
@@ -2840,6 +2845,7 @@ static GradientsUpdateType ParseGradUpdateType(const wstring& s)
     else if (EqualCI(s, L"adagrad"))                 return GradientsUpdateType::AdaGrad;
     else if (EqualCI(s, L"rmsProp"))                 return GradientsUpdateType::RmsProp;
     else if (EqualCI(s, L"fsAdagrad"))               return GradientsUpdateType::FSAdaGrad;
+    else if (EqualCI(s, L"adam"))                    return GradientsUpdateType::Adam;
     // legacy, deprecated
     else if (EqualCI(s, L"normal") || EqualCI(s, L"simple")) return GradientsUpdateType::None;
     else InvalidArgument("ParseGradUpdateType: Invalid Gradient Updating Type. Valid values are (none | adagrad | rmsProp | fsAdagrad )");
@@ -3006,6 +3012,11 @@ SGDParams::SGDParams(const ConfigRecordType& configSGD, size_t sizeofElemType)
     m_rpi.max = configSGD(L"rms_wgt_max", 10.0);
     m_rpi.gamma = configSGD(L"rms_gamma", 0.99);
 
+    // Adam settings
+    m_adam.meanMomentum = configSGD(L"adam_meanMomentum", 0.9);
+    m_adam.varMomentum = configSGD(L"adam_varMomentum", 0.999);
+    m_adam.epsilon = configSGD(L"adam_epsilon", pow(10, -8));
+
     m_needAveMultiplier = configSGD(L"normWithAveMultiplier", true);
     m_L2RegWeight = configSGD(L"L2RegWeight", 0.0);
     m_L1RegWeight = configSGD(L"L1RegWeight", 0.0);

Source/SGDLib/SGD.h

@@ -55,7 +55,8 @@ enum class GradientsUpdateType : int
     None,
     AdaGrad,
     RmsProp,
-    FSAdaGrad
+    FSAdaGrad,
+    Adam
 };
 
 // modelParallelSGD can be combined with dataParallelSGD/modelAveragingSGD/blockMomentumSGD 
@@ -91,6 +92,21 @@ struct RMSPropInfo
     }
 };
 
+struct AdamInfo
+{
+    double meanMomentum; //beta_1
+    double varMomentum;  //beta_2
+    double epsilon;
+
+    AdamInfo()
+    {
+        meanMomentum = 0.9;
+        varMomentum = 0.999;
+        epsilon = pow(10, -8);
+    }
+};
+
+
 struct GradientUpdateInfo
 {
     GradientsUpdateType type = GradientsUpdateType::AdaGrad;
@@ -254,6 +270,7 @@ protected:
 
     GradientUpdateInfo m_gradType;
     RMSPropInfo m_rpi;
+    AdamInfo m_adam;
 
     size_t m_numMBsToShowResult = 0;
     size_t m_firstMBsToShowResult = 0;