COMPMID-519: Add support for Lower and Upper Bounded RELU for CL/NEON

Change-Id: I7b16216ac59c899a33942bf17757b54535256d7a
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/86172
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>

7 files changed, 65 insertions, 12 deletions

diff --git a/arm_compute/core/Types.h b/arm_compute/core/Types.h
index 5eaaee6b7b..b90798e5ff 100644
--- a/arm_compute/core/Types.h
+++ b/arm_compute/core/Types.h
@@ -509,24 +509,25 @@ public:
     /** Available activation functions */
     enum class ActivationFunction
     {
-        LOGISTIC,     /**< Logistic */
-        TANH,         /**< Hyperbolic tangent */
-        RELU,         /**< Rectifier */
-        BOUNDED_RELU, /**< Bounded Rectifier */
-        LEAKY_RELU,   /**< Leaky Rectifier */
-        SOFT_RELU,    /**< Soft Rectifier */
-        ABS,          /**< Absolute */
-        SQUARE,       /**< Square */
-        SQRT,         /**< Square root */
-        LINEAR        /**< Linear */
+        LOGISTIC,        /**< Logistic ( \f$ f(x) = \frac{1}{1 + e^{-x}} \f$ ) */
+        TANH,            /**< Hyperbolic tangent ( \f$ f(x) = a \cdot tanh(b \cdot x) \f$ ) */
+        RELU,            /**< Rectifier ( \f$ f(x) = max(0,x) \f$ ) */
+        BOUNDED_RELU,    /**< Upper Bounded Rectifier ( \f$ f(x) = min(a, max(0,x)) \f$ ) */
+        LU_BOUNDED_RELU, /**< Lower and Upper Bounded Rectifier ( \f$ f(x) = min(a, max(b,x)) \f$ ) */
+        LEAKY_RELU,      /**< Leaky Rectifier ( \f$ f(x)= log(1+e^x) \f$ ) */
+        SOFT_RELU,       /**< Soft Rectifier ( \f$ f(x)= log(1+e^x) \f$ ) */
+        ABS,             /**< Absolute ( \f$ f(x)= |x| \f$ ) */
+        SQUARE,          /**< Square ( \f$ f(x)= x^2 \f$ )*/
+        SQRT,            /**< Square root ( \f$ f(x) = \sqrt{x} \f$ )*/
+        LINEAR           /**< Linear ( \f$ f(x)= ax + b \f$ ) */
     };
 
     /** Default Constructor
      *
      * @param[in] f The activation function to use.
      * @param[in] a (Optional) The alpha parameter used by some activation functions
-     *              (@ref ActivationFunction::BOUNDED_RELU, @ref ActivationFunction::LINEAR, @ref ActivationFunction::TANH).
-     * @param[in] b (Optional) The beta parameter used by some activation functions (@ref ActivationFunction::LINEAR, @ref ActivationFunction::TANH).
+     *              (@ref ActivationFunction::BOUNDED_RELU, @ref ActivationFunction::LU_BOUNDED_RELU, @ref ActivationFunction::LINEAR, @ref ActivationFunction::TANH).
+     * @param[in] b (Optional) The beta parameter used by some activation functions (@ref ActivationFunction::LINEAR, @ref ActivationFunction::LU_BOUNDED_RELU, @ref ActivationFunction::TANH).
      */
     ActivationLayerInfo(ActivationFunction f, float a = 0.0f, float b = 0.0f)
         : _act(f), _a(a), _b(b)
diff --git a/src/core/CL/cl_kernels/activation_layer.cl b/src/core/CL/cl_kernels/activation_layer.cl
index 119879afd5..4424a66b61 100644
--- a/src/core/CL/cl_kernels/activation_layer.cl
+++ b/src/core/CL/cl_kernels/activation_layer.cl
@@ -76,6 +76,11 @@ inline TYPE brelu_op(TYPE x)
 {
     return min((TYPE)A_VAL, max(0, x));
 }
+// Lower Upper Bounded RELU Activation
+inline TYPE lu_brelu_op(TYPE x)
+{
+    return min(max(x, (TYPE)B_VAL), (TYPE)A_VAL);
+}
 // Leaky RELU Activation
 inline TYPE lrelu_op(TYPE x)
 {
diff --git a/src/core/NEON/kernels/NEActivationLayerKernel.cpp b/src/core/NEON/kernels/NEActivationLayerKernel.cpp
index 3195411e18..4ff26c0c67 100644
--- a/src/core/NEON/kernels/NEActivationLayerKernel.cpp
+++ b/src/core/NEON/kernels/NEActivationLayerKernel.cpp
@@ -73,6 +73,7 @@ void NEActivationLayerKernel::configure(ITensor *input, ITensor *output, Activat
         { ActivationFunction::LOGISTIC, &NEActivationLayerKernel::activation<ActivationFunction::LOGISTIC, float> },
         { ActivationFunction::RELU, &NEActivationLayerKernel::activation<ActivationFunction::RELU, float> },
         { ActivationFunction::BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::BOUNDED_RELU, float> },
+        { ActivationFunction::LU_BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::LU_BOUNDED_RELU, float> },
         { ActivationFunction::LEAKY_RELU, &NEActivationLayerKernel::activation<ActivationFunction::LEAKY_RELU, float> },
         { ActivationFunction::SOFT_RELU, &NEActivationLayerKernel::activation<ActivationFunction::SOFT_RELU, float> },
         { ActivationFunction::SQRT, &NEActivationLayerKernel::activation<ActivationFunction::SQRT, float> },
@@ -89,6 +90,7 @@ void NEActivationLayerKernel::configure(ITensor *input, ITensor *output, Activat
         { ActivationFunction::LOGISTIC, &NEActivationLayerKernel::activation<ActivationFunction::LOGISTIC, float16_t> },
         { ActivationFunction::RELU, &NEActivationLayerKernel::activation<ActivationFunction::RELU, float16_t> },
         { ActivationFunction::BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::BOUNDED_RELU, float16_t> },
+        { ActivationFunction::LU_BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::LU_BOUNDED_RELU, float16_t> },
         { ActivationFunction::SOFT_RELU, &NEActivationLayerKernel::activation<ActivationFunction::SOFT_RELU, float16_t> },
         { ActivationFunction::SQRT, &NEActivationLayerKernel::activation<ActivationFunction::SQRT, float16_t> },
         { ActivationFunction::SQUARE, &NEActivationLayerKernel::activation<ActivationFunction::SQUARE, float16_t> },
@@ -104,6 +106,7 @@ void NEActivationLayerKernel::configure(ITensor *input, ITensor *output, Activat
         { ActivationFunction::LOGISTIC, &NEActivationLayerKernel::activation<ActivationFunction::LOGISTIC, qint8_t> },
         { ActivationFunction::RELU, &NEActivationLayerKernel::activation<ActivationFunction::RELU, qint8_t> },
         { ActivationFunction::BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::BOUNDED_RELU, qint8_t> },
+        { ActivationFunction::LU_BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::LU_BOUNDED_RELU, qint8_t> },
         { ActivationFunction::LEAKY_RELU, &NEActivationLayerKernel::activation<ActivationFunction::LEAKY_RELU, qint8_t> },
         { ActivationFunction::SOFT_RELU, &NEActivationLayerKernel::activation<ActivationFunction::SOFT_RELU, qint8_t> },
         { ActivationFunction::SQRT, &NEActivationLayerKernel::activation<ActivationFunction::SQRT, qint8_t> },
@@ -118,6 +121,7 @@ void NEActivationLayerKernel::configure(ITensor *input, ITensor *output, Activat
         { ActivationFunction::LOGISTIC, &NEActivationLayerKernel::activation<ActivationFunction::LOGISTIC, qint16_t> },
         { ActivationFunction::RELU, &NEActivationLayerKernel::activation<ActivationFunction::RELU, qint16_t> },
         { ActivationFunction::BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::BOUNDED_RELU, qint16_t> },
+        { ActivationFunction::LU_BOUNDED_RELU, &NEActivationLayerKernel::activation<ActivationFunction::LU_BOUNDED_RELU, qint16_t> },
         { ActivationFunction::LEAKY_RELU, &NEActivationLayerKernel::activation<ActivationFunction::LEAKY_RELU, qint16_t> },
         { ActivationFunction::SOFT_RELU, &NEActivationLayerKernel::activation<ActivationFunction::SOFT_RELU, qint16_t> },
         { ActivationFunction::SQRT, &NEActivationLayerKernel::activation<ActivationFunction::SQRT, qint16_t> },
@@ -211,6 +215,15 @@ typename std::enable_if<std::is_same<T, float16_t>::value, void>::type NEActivat
                     }
                 };
                 break;
+            case ActivationFunction::LU_BOUNDED_RELU:
+                tmp =
+                {
+                    {
+                        vminq_f16(a, vmaxq_f16(b, in.val[0])),
+                        vminq_f16(a, vmaxq_f16(b, in.val[1]))
+                    }
+                };
+                break;
             case ActivationFunction::LINEAR:
                 tmp =
                 {
@@ -370,6 +383,17 @@ typename std::enable_if<std::is_same<T, float>::value, void>::type NEActivationL
                     }
                 };
                 break;
+            case ActivationFunction::LU_BOUNDED_RELU:
+                tmp =
+                {
+                    {
+                        vminq_f32(a, vmaxq_f32(b, in.val[0])),
+                        vminq_f32(a, vmaxq_f32(b, in.val[1])),
+                        vminq_f32(a, vmaxq_f32(b, in.val[2])),
+                        vminq_f32(a, vmaxq_f32(b, in.val[3])),
+                    }
+                };
+                break;
             case ActivationFunction::LEAKY_RELU:
                 tmp =
                 {
@@ -471,6 +495,9 @@ typename std::enable_if<std::is_same<T, int8_t>::value, void>::type NEActivation
             case ActivationFunction::BOUNDED_RELU:
                 tmp = vminq_qs8(a, vmaxq_qs8(CONST_0, in));
                 break;
+            case ActivationFunction::LU_BOUNDED_RELU:
+                tmp = vminq_qs8(a, vmaxq_qs8(b, in));
+                break;
             case ActivationFunction::LEAKY_RELU:
                 tmp = vbslq_s8(vcgtq_s8(in, CONST_0), in, vmulq_qs8(a, in, fixed_point_position));
                 break;
@@ -562,6 +589,15 @@ typename std::enable_if<std::is_same<T, qint16_t>::value, void>::type NEActivati
                     }
                 };
                 break;
+            case ActivationFunction::LU_BOUNDED_RELU:
+                tmp =
+                {
+                    {
+                        vminq_qs16(a, vmaxq_qs16(b, in.val[0])),
+                        vminq_qs16(a, vmaxq_qs16(b, in.val[1])),
+                    }
+                };
+                break;
             case ActivationFunction::LEAKY_RELU:
                 tmp =
                 {
diff --git a/src/core/Utils.cpp b/src/core/Utils.cpp
index cf8e1940ec..66d3fe8f78 100644
--- a/src/core/Utils.cpp
+++ b/src/core/Utils.cpp
@@ -156,6 +156,7 @@ const std::string &arm_compute::string_from_activation_func(ActivationLayerInfo:
         { ActivationLayerInfo::ActivationFunction::LOGISTIC, "LOGISTIC" },
         { ActivationLayerInfo::ActivationFunction::RELU, "RELU" },
         { ActivationLayerInfo::ActivationFunction::BOUNDED_RELU, "BRELU" },
+        { ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU, "LU_BRELU" },
         { ActivationLayerInfo::ActivationFunction::LEAKY_RELU, "LRELU" },
         { ActivationLayerInfo::ActivationFunction::SOFT_RELU, "SRELU" },
         { ActivationLayerInfo::ActivationFunction::SQRT, "SQRT" },
diff --git a/tests/TypePrinter.h b/tests/TypePrinter.h
index c207c1d634..bbccaadc6d 100644
--- a/tests/TypePrinter.h
+++ b/tests/TypePrinter.h
@@ -254,6 +254,9 @@ inline ::std::ostream &operator<<(::std::ostream &os, const ActivationLayerInfo:
         case ActivationLayerInfo::ActivationFunction::BOUNDED_RELU:
             os << "BOUNDED_RELU";
             break;
+        case ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU:
+            os << "LU_BOUNDED_RELU";
+            break;
         case ActivationLayerInfo::ActivationFunction::LEAKY_RELU:
             os << "LEAKY_RELU";
             break;
diff --git a/tests/datasets/ActivationFunctionsDataset.h b/tests/datasets/ActivationFunctionsDataset.h
index 3e4f408614..31323dc8be 100644
--- a/tests/datasets/ActivationFunctionsDataset.h
+++ b/tests/datasets/ActivationFunctionsDataset.h
@@ -46,6 +46,7 @@ public:
                             ActivationLayerInfo::ActivationFunction::LOGISTIC,
                             ActivationLayerInfo::ActivationFunction::RELU,
                             ActivationLayerInfo::ActivationFunction::BOUNDED_RELU,
+                            ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU,
                             ActivationLayerInfo::ActivationFunction::LEAKY_RELU,
                             ActivationLayerInfo::ActivationFunction::SOFT_RELU,
                             ActivationLayerInfo::ActivationFunction::SQRT,
diff --git a/tests/validation/CPP/ActivationLayer.cpp b/tests/validation/CPP/ActivationLayer.cpp
index fa393be5e1..8fcacca1e2 100644
--- a/tests/validation/CPP/ActivationLayer.cpp
+++ b/tests/validation/CPP/ActivationLayer.cpp
@@ -66,6 +66,9 @@ SimpleTensor<T> activation_layer(const SimpleTensor<T> &src, ActivationLayerInfo
             case ActivationLayerInfo::ActivationFunction::BOUNDED_RELU:
                 dst[i] = std::min<T>(a, std::max(static_cast<T>(0), x));
                 break;
+            case ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU:
+                dst[i] = std::min<T>(a, std::max<T>(b, x));
+                break;
             case ActivationLayerInfo::ActivationFunction::LEAKY_RELU:
                 dst[i] = (x > 0) ? x : a * x;
                 break;
@@ -125,6 +128,9 @@ SimpleTensor<T> activation_layer(const SimpleTensor<T> &src, ActivationLayerInfo
             case ActivationLayerInfo::ActivationFunction::BOUNDED_RELU:
                 dst[i] = min(a, max(const_0, x)).raw();
                 break;
+            case ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU:
+                dst[i] = min(a, max(b, x)).raw();
+                break;
             case ActivationLayerInfo::ActivationFunction::LEAKY_RELU:
                 dst[i] = (x > const_0) ? x.raw() : mul(a, x).raw();
                 break;