shrink operator (#5022)

docs/developer-guide/operators.md

@@ -72,6 +72,7 @@
 * [RNN](#rnn)
 * [Scale](#scale)
 * [SELU](#selu)
+* [Shrink](#shrink)
 * [ShuffleChannel](#shufflechannel)
 * [Sigmoid](#sigmoid)
 * [Slice](#slice)
@@ -1675,6 +1676,21 @@ else        y = x * lambda
 | 0         | alpha         | float | 1.67326324f|                  |
 | 1         | lambda        | float | 1.050700987f|                 |
 
+# Shrink
+```
+if x < -lambd y = x + bias
+if x >  lambd y = x - bias
+else          y = x
+```
+
+* one_blob_only
+* support_inplace
+
+| param id  | name          | type  | default   | description       |
+| --------- | ------------- | ----- | --------- | ----------------- |
+| 0         | bias          | float | 0.0f      |                   |
+| 1         | lambd         | float | 0.5f      |                   |
+
 # ShuffleChannel
 ```
 if reverse == 0     y = shufflechannel(x) by group

src/CMakeLists.txt

@@ -165,6 +165,7 @@ ncnn_add_layer(CopyTo)
 ncnn_add_layer(Erf)
 ncnn_add_layer(Diag)
 ncnn_add_layer(CELU)
+ncnn_add_layer(Shrink)
 
 if(NCNN_VULKAN)
     ncnn_add_shader(${CMAKE_CURRENT_SOURCE_DIR}/convert_ycbcr.comp)

src/layer/shrink.cpp

@@ -0,0 +1,54 @@
+// Tencent is pleased to support the open source community by making ncnn available.
+//
+// Copyright (C) 2017 THL A29 Limited, a Tencent company. All rights reserved.
+//
+// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+// in compliance with the License. You may obtain a copy of the License at
+//
+// https://opensource.org/licenses/BSD-3-Clause
+//
+// Unless required by applicable law or agreed to in writing, software distributed
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+#include "shrink.h"
+
+namespace ncnn {
+
+Shrink::Shrink()
+{
+    one_blob_only = true;
+    support_inplace = true;
+}
+
+int Shrink::load_param(const ParamDict& pd)
+{
+    bias = pd.get(0, 0.0f);
+    lambd = pd.get(1, 0.5f);
+
+    return 0;
+}
+
+int Shrink::forward_inplace(Mat& bottom_top_blob, const Option& opt) const
+{
+    int w = bottom_top_blob.w;
+    int h = bottom_top_blob.h;
+    int channels = bottom_top_blob.c;
+    int size = w * h;
+
+    #pragma omp parallel for num_threads(opt.num_threads)
+    for (int q = 0; q < channels; q++)
+    {
+        float* ptr = bottom_top_blob.channel(q);
+
+        for (int i = 0; i < size; i++)
+        {
+            ptr[i] = ptr[i] < -lambd ? ptr[i] + bias : ptr[i] > lambd ? ptr[i] - bias : ptr[i];
+        }
+    }
+
+    return 0;
+}
+
+} // namespace ncnn

src/layer/shrink.h

@@ -0,0 +1,37 @@
+// Tencent is pleased to support the open source community by making ncnn available.
+//
+// Copyright (C) 2017 THL A29 Limited, a Tencent company. All rights reserved.
+//
+// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+// in compliance with the License. You may obtain a copy of the License at
+//
+// https://opensource.org/licenses/BSD-3-Clause
+//
+// Unless required by applicable law or agreed to in writing, software distributed
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+#ifndef LAYER_SHRINK_H
+#define LAYER_SHRINK_H
+
+#include "layer.h"
+
+namespace ncnn {
+
+class Shrink : public Layer
+{
+public:
+    Shrink();
+
+    virtual int load_param(const ParamDict& pd);
+    virtual int forward_inplace(Mat& bottom_top_blob, const Option& opt) const;
+
+public:
+    float bias;
+    float lambd;
+};
+
+} // namespace ncnn
+
+#endif // LAYER_SHRINK_H

tests/CMakeLists.txt

@@ -143,6 +143,7 @@ ncnn_add_layer_test(ROIPooling)
 ncnn_add_layer_test(ROIAlign)
 ncnn_add_layer_test(Scale)
 ncnn_add_layer_test(SELU)
+ncnn_add_layer_test(Shrink)
 ncnn_add_layer_test(ShuffleChannel)
 ncnn_add_layer_test(Sigmoid)
 ncnn_add_layer_test(Slice)

tests/test_shrink.cpp

@@ -0,0 +1,76 @@
+// Tencent is pleased to support the open source community by making ncnn available.
+//
+// Copyright (C) 2021 THL A29 Limited, a Tencent company. All rights reserved.
+//
+// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+// in compliance with the License. You may obtain a copy of the License at
+//
+// https://opensource.org/licenses/BSD-3-Clause
+//
+// Unless required by applicable law or agreed to in writing, software distributed
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+#include "layer/shrink.h"
+#include "testutil.h"
+
+static int test_shrink(const ncnn::Mat& a, float lambd, float bias)
+{
+    ncnn::ParamDict pd;
+    pd.set(0, bias);
+    pd.set(1, lambd);
+
+    std::vector<ncnn::Mat> weights(0);
+
+    int ret = test_layer<ncnn::Shrink>("Shrink", pd, weights, a);
+    if (ret != 0)
+    {
+        fprintf(stderr, "test_shrink failed a.dims=%d a=(%d %d %d %d)\n", a.dims, a.w, a.h, a.d, a.c);
+    }
+
+    return ret;
+}
+
+static int test_shrink_0()
+{
+    return 0
+           || test_shrink(RandomMat(12, 24, 8, 3), 0.5f, 5.0f)
+           || test_shrink(RandomMat(9, 7, 16, 4), 1.0f, 0.3f)
+           || test_shrink(RandomMat(6, 9, 4, 3), 4.5, 6.1);
+}
+
+static int test_shrink_1()
+{
+    return 0
+           || test_shrink(RandomMat(12, 6, 24), 0.5f, 5.0f)
+           || test_shrink(RandomMat(7, 8, 24), 1.0f, 0.3f)
+           || test_shrink(RandomMat(3, 4, 5), 4.5, 6.1);
+}
+
+static int test_shrink_2()
+{
+    return 0
+           || test_shrink(RandomMat(5, 7), 3.4f, 0.3f)
+           || test_shrink(RandomMat(7, 9), 3.1f, 4.0f)
+           || test_shrink(RandomMat(3, 5), 2.0f, 4.0f);
+}
+
+static int test_shrink_3()
+{
+    return 0
+           || test_shrink(RandomMat(25), 3.4f, 0.3f)
+           || test_shrink(RandomMat(63), 3.1f, 4.0f)
+           || test_shrink(RandomMat(1024), 2.0f, 4.0f);
+}
+
+int main()
+{
+    SRAND(7767517);
+
+    return 0
+           || test_shrink_0()
+           || test_shrink_1()
+           || test_shrink_2()
+           || test_shrink_3();
+}

tools/onnx/onnx2ncnn.cpp

@@ -3894,6 +3894,10 @@ int main(int argc, char** argv)
         {
             fprintf(pp, "%-16s", "BinaryOp");
         }
+        else if (op == "Shrink")
+        {
+            fprintf(pp, "%-16s", "Shrink");
+        }
         else if (op == "ShuffleChannel")
         {
             fprintf(pp, "%-16s", "ShuffleChannel");
@@ -5746,6 +5750,13 @@ int main(int argc, char** argv)
                 fprintf(pp, " 2=%e", b);
             }
         }
+        else if (op == "Shrink")
+        {
+            float bias = get_node_attr_f(node, "bias", 0.0f);
+            float lambd = get_node_attr_f(node, "lambd", 0.5f);
+            fprintf(pp, " 0=%e", bias);
+            fprintf(pp, " 1=%e", lambd);
+        }
         else if (op == "ShuffleChannel")
         {
             int group = get_node_attr_i(node, "group", 1);