[operator] Add logsigmoid activation function

benchmark/opperf/nd_operations/nn_activation_operators.py

@@ -36,9 +36,10 @@
 8. Activation
     8.1 relu
     8.2 sigmoid
-    8.3 softrelu
-    8.4 softsign
-    8.5 tanh
+    8.3 log_sigmoid
+    8.4 softrelu
+    8.5 softsign
+    8.6 tanh
 
 """
 

benchmark/opperf/rules/default_params.py

@@ -375,7 +375,7 @@
 
 # For NN operators
 DEFAULT_ACT_TYPE_LR = ['leaky', 'elu', 'selu', 'gelu']
-DEFAULT_ACT_TYPE_ACTIVATION = ['relu', 'sigmoid', 'softrelu', 'softsign', 'tanh']
+DEFAULT_ACT_TYPE_ACTIVATION = ['relu', 'sigmoid', 'log_sigmoid', 'softrelu', 'softsign', 'tanh']
 DEFAULT_LABEL_SOFTMAX = [(1024, 1024), (10000, 1), (10000, 100)]
 
 DEFAULT_LABEL_SOFTMAX_LARGE_TENSOR = [(2**32, 1)]

python/mxnet/amp/lists/symbol_bf16.py

@@ -288,6 +288,7 @@
     'hard_sigmoid',
     'identity',
     'logical_not',
+    'log_sigmoid'
     'max_axis',
     'max',
     'min',

python/mxnet/amp/lists/symbol_fp16.py

@@ -395,6 +395,7 @@
     'lamb_update_phase1',
     'lamb_update_phase2',
     'logical_not',
+    'log_sigmoid',
     'max',
     'min',
     'mp_lamb_update_phase1',

python/mxnet/ndarray/ndarray.py

@@ -2171,6 +2171,14 @@ def log1p(self, *args, **kwargs):
         """
         return op.log1p(self, *args, **kwargs)
 
+    def log_sigmoid(self, *args, **kwargs):
+        """Convenience fluent method for :py:func:`log_sigmoid`.
+
+        The arguments are the same as for :py:func:`log_sigmoid`, with
+        this array as data.
+        """
+        return op.log_sigmoid(self, *args, **kwargs)
+
     def sqrt(self, *args, **kwargs):
         """Convenience fluent method for :py:func:`sqrt`.
 

python/mxnet/numpy/multiarray.py

@@ -2260,6 +2260,14 @@ def log1p(self, *args, **kwargs):
         """
         raise AttributeError('mxnet.numpy.ndarray object has no attribute log1p')
 
+    def log_sigmoid(self, *args, **kwargs):
+        """Convenience fluent method for :py:func:`log_sigmoid`.
+
+        The arguments are the same as for :py:func:`log_sigmoid`, with
+        this array as data.
+        """
+        raise AttributeError('mxnet.numpy.ndarray object has no attribute log_sigmoid')
+
     def sqrt(self, *args, **kwargs):
         """Convenience fluent method for :py:func:`sqrt`.
 

python/mxnet/symbol/symbol.py

@@ -2519,6 +2519,14 @@ def log1p(self, *args, **kwargs):
         """
         return op.log1p(self, *args, **kwargs)
 
+    def log_sigmoid(self, *args, **kwargs):
+        """Convenience fluent method for :py:func:`log_sigmoid`.
+
+        The arguments are the same as for :py:func:`log_sigmoid`, with
+        this array as data.
+        """
+        return op.log_sigmoid(self, *args, **kwargs)
+
     def sqrt(self, *args, **kwargs):
         """Convenience fluent method for :py:func:`sqrt`.
 

src/api/operator/numpy_extension/npx_activation_op.cc

@@ -34,6 +34,8 @@ inline int String2MXNetActType(const std::string& s) {
     return activation::kReLU;
   } else if (s == "sigmoid") {
     return activation::kSigmoid;
+  } else if (s == "log_sigmoid") {
+    return activation::kLogSigmoid;
   } else if (s == "tanh") {
     return activation::kTanh;
   } else if (s == "softrelu") {

src/common/cuda/rtc/backward_functions-inl.h

@@ -40,8 +40,14 @@ backward_relu(const DTypeGrad grad, const DType val) {
 
 template <typename DType, typename DTypeGrad>
 __device__ inline mixed_type<DTypeGrad, DType>
-backward_sigmoid(const DTypeGrad grad, const DType out) {
-  return grad * out * (1 - out);
+backward_sigmoid(const DTypeGrad grad, const DType val) {
+  return grad * val * (1 - val);
+}
+
+template <typename DType, typename DTypeGrad>
+__device__ inline mixed_type<DTypeGrad, DType>
+backward_log_sigmoid(const DTypeGrad grad, const DType val) {
+  return grad * 1 / (1 + op::exp(val));
 }
 
 template <typename DType, typename DTypeGrad>

src/common/cuda/rtc/forward_functions-inl.h

@@ -685,6 +685,15 @@ __device__ inline DType sigmoid(const DType val) {
   }
 }
 
+template <typename DType>
+__device__ inline DType log_sigmoid(const DType val) {
+  if (type_util::has_double_or_integral<DType>::value) {
+    return ::log(1./(1 + ::exp(-val)));
+  } else {
+    return ::logf(1.f/(1 + expf(-val)));
+  }
+}
+
 template <typename DType>
 __device__ inline DType softrelu(const DType val) {
   if (type_util::has_double_or_integral<DType>::value) {

src/operator/fusion/fused_op-inl.h

@@ -56,6 +56,7 @@ const std::map<std::string, std::vector<std::vector<std::string>>> ops_desc = {
   {"_backward_amp_cast"                , {{"op::identity(%)", "_0"}}},
   {"relu"                              , {{"op::relu(%)", "_0"}}},
   {"sigmoid"                           , {{"op::sigmoid(%)", "_0"}}},
+  {"log_sigmoid"                       , {{"op::log_sigmoid(%)", "_0"}}},
   {"softsign"                          , {{"op::softsign(%)", "_0"}}},
   {"exp"                               , {{"op::exp(%)", "_0"}}},
   {"expm1"                             , {{"op::expm1(%)", "_0"}}},
@@ -135,6 +136,7 @@ const std::map<std::string, std::vector<std::vector<std::string>>> ops_desc = {
   {"logical_not"                       , {{"op::logical_not(%)", "_0"}}},
   {"_backward_relu"                    , {{"op::backward_relu(%, %)", "_0", "_1"}}},
   {"_backward_sigmoid"                 , {{"op::backward_sigmoid(%, %)", "_0", "_1"}}},
+  {"_backward_log_sigmoid"             , {{"op::backward_log_sigmoid(%, %)", "_0", "_1"}}},
   {"_backward_expm1"                   , {{"op::backward_expm1(%, %)", "_0", "_1"}}},
   {"_backward_log"                     , {{"op::backward_log(%, %)", "_0", "_1"}}},
   {"_backward_log10"                   , {{"op::backward_log10(%, %)", "_0", "_1"}}},

src/operator/mshadow_op.h

@@ -411,6 +411,10 @@ MXNET_UNARY_MATH_OP(sigmoid, 1.0f / (1.0f + math::exp(-a)));
 
 MXNET_UNARY_MATH_OP(sigmoid_grad, math::id(a) * (1.0f - math::id(a)));
 
+MXNET_UNARY_MATH_OP(log_sigmoid, math::log(1.0f / (1.0f + math::exp(-a))));
+
+MXNET_UNARY_MATH_OP(log_sigmoid_grad, 1.0f / (1.0f + math::exp(a)));
+
 MXNET_UNARY_MATH_OP(softsign, a / (1.0f + math::fabs(a)));
 
 MXNET_UNARY_MATH_OP(softsign_grad, 1.0f /  math::sqr(1.0f + math::fabs(a)));

src/operator/nn/activation-inl.h

@@ -47,7 +47,7 @@ namespace activation {
 enum ActivationOpInputs {kData};
 enum ActivationOpOutputs {kOut};
 enum ActivationOpResource {kTempSpace};
-enum ActivationOpType {kReLU, kSigmoid, kTanh, kSoftReLU, kSoftSign};
+enum ActivationOpType {kReLU, kSigmoid, kLogSigmoid, kTanh, kSoftReLU, kSoftSign};
 
 // Get the number of inputs to the gradient depending on the activation type
 int GradNumInputs(int act_type);
@@ -60,6 +60,7 @@ struct ActivationParam : public dmlc::Parameter<ActivationParam> {
     DMLC_DECLARE_FIELD(act_type)
     .add_enum("relu", activation::kReLU)
     .add_enum("sigmoid", activation::kSigmoid)
+    .add_enum("log_sigmoid", activation::kLogSigmoid)
     .add_enum("tanh", activation::kTanh)
     .add_enum("softrelu", activation::kSoftReLU)
     .add_enum("softsign", activation::kSoftSign)
@@ -75,6 +76,8 @@ struct ActivationParam : public dmlc::Parameter<ActivationParam> {
         return "relu";
       case activation::kSigmoid:
         return "sigmoid";
+      case activation::kLogSigmoid:
+        return "log_sigmoid";
       case activation::kTanh:
         return "tanh";
       case activation::kSoftReLU:
@@ -159,6 +162,10 @@ void ActivationComputeImpl(const nnvm::NodeAttrs& attrs, const OpContext &ctx,
       ActivationForward<xpu, mshadow_op::sigmoid, mshadow_op::sigmoid_grad>(
           ctx, inputs[0], req[0], outputs[0]);
       break;
+    case activation::kLogSigmoid:
+      ActivationForward<xpu, mshadow_op::log_sigmoid, mshadow_op::log_sigmoid_grad>(
+          ctx, inputs[0], req[0], outputs[0]);
+      break;
     case activation::kTanh:
       ActivationForward<xpu, mshadow_op::tanh, mshadow_op::tanh_grad>(
           ctx, inputs[0], req[0], outputs[0]);
@@ -190,6 +197,10 @@ void ActivationGradComputeImpl(const nnvm::NodeAttrs& attrs, const OpContext &ct
       ActivationBackward<xpu, mshadow_op::sigmoid, mshadow_op::sigmoid_grad>(
           ctx, inputs[0], inputs[1], req[0], outputs[0]);
       break;
+    case activation::kLogSigmoid:
+      ActivationBackward<xpu, mshadow_op::log_sigmoid, mshadow_op::log_sigmoid_grad>(
+          ctx, inputs[0], inputs[1], req[0], outputs[0]);
+      break;
     case activation::kTanh:
       ActivationBackward<xpu, mshadow_op::tanh, mshadow_op::tanh_grad>(
           ctx, inputs[0], inputs[1], req[0], outputs[0]);

src/operator/nn/activation.cc

@@ -51,6 +51,7 @@ int GradNumInputs(int act_type) {
       case kSoftSign:
       case kTanh:
       case kSigmoid:
+      case kLogSigmoid:
         return 3;
       default:
         CHECK(false) << "missing activation type";
@@ -91,6 +92,7 @@ struct ActivationGrad {
         case kSoftSign:
         case kTanh:
         case kSigmoid:
+        case kLogSigmoid:
           heads.push_back(n->inputs[activation::kData]);
           break;
         default:
@@ -168,6 +170,7 @@ The following activation functions are supported:
 
 - `relu`: Rectified Linear Unit, :math:`y = max(x, 0)`
 - `sigmoid`: :math:`y = \frac{1}{1 + exp(-x)}`
+- `log_sigmoid`: :math:`y = log(\frac{1}{1 + exp(-x)})`
 - `tanh`: Hyperbolic tangent, :math:`y = \frac{exp(x) - exp(-x)}{exp(x) + exp(-x)}`
 - `softrelu`: Soft ReLU, or SoftPlus, :math:`y = log(1 + exp(x))`
 - `softsign`: :math:`y = \frac{x}{1 + abs(x)}`

src/operator/nn/activation.cu

@@ -115,6 +115,9 @@ void ActivationGradCompute<gpu>(const nnvm::NodeAttrs& attrs,
       } else if (act_type == activation::kSigmoid) {
         ActivationBackward<gpu, mshadow_op::sigmoid, mshadow_op::sigmoid_grad>(
           ctx, inputs.at(0), inputs.at(1), req[0], outputs[0]);
+      } else if (act_type == activation::kLogSigmoid) {
+        ActivationBackward<gpu, mshadow_op::log_sigmoid, mshadow_op::log_sigmoid_grad>(
+          ctx, inputs.at(0), inputs.at(1), req[0], outputs[0]);
       } else {
         LOG(FATAL) << "unknown activation type";
       }

src/operator/nn/mkldnn/mkldnn_act.cc

@@ -43,6 +43,7 @@ namespace op {
 bool SupportMKLDNNAct(const ActivationParam& param) {
   return param.act_type == activation::kReLU
       || param.act_type == activation::kSigmoid
+      || param.act_type == activation::kLogSigmoid
       || param.act_type == activation::kSoftReLU
       || param.act_type == activation::kTanh;
 }
@@ -83,6 +84,8 @@ mkldnn::algorithm GetMKLDNNActAlgo(const ActivationParam& param) {
       return mkldnn::algorithm::eltwise_relu;
     case activation::kSigmoid:
       return mkldnn::algorithm::eltwise_logistic;
+    case activation::kLogSigmoid:
+      return mkldnn::algorithm::eltwise_logsigmoid;
     case activation::kTanh:
       return mkldnn::algorithm::eltwise_tanh;
     case activation::kSoftReLU:

src/operator/operator_tune.cc

@@ -236,6 +236,8 @@ IMPLEMENT_UNARY_WORKLOAD_FWD(mxnet::op::mshadow_op::reciprocal);  // NOLINT()
 IMPLEMENT_UNARY_WORKLOAD_BWD(mxnet::op::mshadow_op::reciprocal_grad);  // NOLINT()
 IMPLEMENT_UNARY_WORKLOAD_FWD(mxnet::op::mshadow_op::sigmoid);  // NOLINT()
 IMPLEMENT_UNARY_WORKLOAD_BWD(mxnet::op::mshadow_op::sigmoid_grad);  // NOLINT()
+IMPLEMENT_UNARY_WORKLOAD_FWD(mxnet::op::mshadow_op::log_sigmoid);  // NOLINT()
+IMPLEMENT_UNARY_WORKLOAD_BWD(mxnet::op::mshadow_op::log_sigmoid_grad);  // NOLINT()
 IMPLEMENT_UNARY_WORKLOAD_FWD(mxnet::op::mshadow_op::softsign);  // NOLINT()
 IMPLEMENT_UNARY_WORKLOAD_BWD(mxnet::op::mshadow_op::softsign_grad);  // NOLINT()
 IMPLEMENT_UNARY_WORKLOAD_FWD(mxnet::op::mshadow_op::relu);  // NOLINT()

src/operator/tensor/elemwise_unary_op_basic.cc

@@ -196,6 +196,23 @@ MXNET_OPERATOR_REGISTER_BINARY(_backward_softsign)
 .set_attr<FCompute>("FCompute<cpu>", ElemwiseBinaryOp::Compute<cpu,
   unary_bwd<mshadow_op::softsign_grad> >);
 
+// log_sigmoid
+MXNET_OPERATOR_REGISTER_UNARY(log_sigmoid)
+MXNET_ADD_SPARSE_OP_ALIAS(log_sigmoid)
+.describe(R"code(Computes log_sigmoid of x element-wise.
+
+.. math::
+   y = log(1 / (1 + exp(-x)))
+
+The storage type of ``log_sigmoid`` output is always dense
+
+)code" ADD_FILELINE)
+.set_attr<FCompute>("FCompute<cpu>", UnaryOp::Compute<cpu, mshadow_op::log_sigmoid>)
+.set_attr<nnvm::FGradient>("FGradient", ElemwiseGradUseIn{"_backward_log_sigmoid"});
+
+MXNET_OPERATOR_REGISTER_BINARY_WITH_SPARSE_CPU(_backward_log_sigmoid,
+                                               unary_bwd<mshadow_op::log_sigmoid_grad>);
+
 // copy
 static void CopyEx(const nnvm::NodeAttrs& attrs,
                    const OpContext& ctx,

src/operator/tensor/elemwise_unary_op_basic.cu

@@ -39,6 +39,12 @@ NNVM_REGISTER_OP(sigmoid)
 NNVM_REGISTER_OP(_backward_sigmoid)
 .set_attr<FCompute>("FCompute<gpu>", ElemwiseBinaryRTCCompute{"backward_sigmoid"});
 
+NNVM_REGISTER_OP(log_sigmoid)
+.set_attr<FCompute>("FCompute<gpu>", UnaryRTCCompute{"log_sigmoid"});
+
+NNVM_REGISTER_OP(_backward_log_sigmoid)
+.set_attr<FCompute>("FCompute<gpu>", ElemwiseBinaryRTCCompute{"backward_log_sigmoid"});
+
 NNVM_REGISTER_OP(hard_sigmoid)
 .set_attr<FCompute>("FCompute<gpu>", HardSigmoidForward<gpu>);
 

tests/cpp/operator/activation_perf.cc

@@ -43,6 +43,7 @@ TEST(ACTIVATION_PERF, ExecuteBidirectional) {
   vector<string> activations = {
     "relu",
     "sigmoid",
+    "log_sigmoid",
     "tanh",
     "softrelu",
     "softsign"

tests/python/unittest/test_operator.py

@@ -677,6 +677,21 @@ def fsigmoid(a):
     check_symbolic_forward(y, [xa], [ya])
     check_symbolic_backward(y, [xa], [np.ones(shape)], [ya * (1 - ya)])
 
+def test_log_sigmoid():
+    def flog_sigmoid(a):
+        return np.log(np.divide(1.0, np.add(1.0, np.exp(-a))))
+    def flog_sigmoid_grad(a):
+        return np.divide(1.0, np.add(1.0, np.exp(a)))
+    shape = (3, 4)
+    x = mx.symbol.Variable("x")
+    y = mx.sym.log_sigmoid(x)
+    xa = np.random.uniform(low=-1.0,high=1.0,size=shape)
+    ya = flog_sigmoid(xa)
+    ya_grad = flog_sigmoid_grad(xa)
+    check_numeric_gradient(y, [xa], numeric_eps=1E-3)
+    check_symbolic_forward(y, [xa], [ya])
+    check_symbolic_backward(y, [xa], [np.ones(shape)], [ya_grad])
+
 def test_shape_array():
     for i in range(1,6):
         shape = rand_shape_nd(i)
@@ -8697,7 +8712,7 @@ def test_get_operator_arguments():
     assert isinstance(operator_arguments, OperatorArguments)
     assert operator_arguments.names == ['data', 'act_type']
     assert operator_arguments.types \
-        == ['NDArray-or-Symbol', "{'relu', 'sigmoid', 'softrelu', 'softsign', 'tanh'}, required"]
+        == ['NDArray-or-Symbol', "{'log_sigmoid', 'relu', 'sigmoid', 'softrelu', 'softsign', 'tanh'}, required"]
     assert operator_arguments.narg == 2