Add support for ReLU6 op in CAFFE (#621)

Add support for Clip op in CAFFE
Co-authored-by: Nriccardo <rgall@sertiscorp.com>

third_party/caffe/Dockerfile

@@ -30,6 +30,8 @@ WORKDIR $CAFFE_ROOT
 # FIXME: use ARG instead of ENV once DockerHub supports this
 # https://github.com/docker/hub-feedback/issues/460
 ENV CLONE_TAG=1.0
+# To enable Clip operation in CAFFE during validation, it's needed to set CLONE_TAG=master
+# ENV CLONE_TAG=master
 
 # ImportError in system pip wrappers after an upgrade.
 # https://github.com/pypa/pip/issues/5599

third_party/caffe/caffe.proto

@@ -437,7 +437,7 @@ message ParamSpec {
 // NOTE
 // Update the next available ID when you add a new LayerParameter field.
 //
-// LayerParameter next available layer-specific ID: 147 (last added: recurrent_param)
+// LayerParameter next available layer-specific ID: 149 (last added: clip_param)
 message LayerParameter {
   optional string name = 1; // the layer name
   optional string type = 2; // the layer type
@@ -494,6 +494,7 @@ message LayerParameter {
   optional ArgMaxParameter argmax_param = 103;
   optional BatchNormParameter batch_norm_param = 139;
   optional BiasParameter bias_param = 141;
+  optional ClipParameter clip_param = 148;
   optional ConcatParameter concat_param = 104;
   optional ContrastiveLossParameter contrastive_loss_param = 105;
   optional ConvolutionParameter convolution_param = 106;
@@ -778,6 +779,12 @@ message ArgMaxParameter {
   optional int32 axis = 3;
 }
 
+// Message that stores parameters used by ClipLayer
+message ClipParameter {
+  required float min = 1;
+  required float max = 2;
+}
+
 message ConcatParameter {
   // The axis along which to concatenate -- may be negative to index from the
   // end (e.g., -1 for the last axis).  Other axes must have the

tools/python/transform/caffe_converter.py

@@ -164,6 +164,7 @@ class CaffeConverter(base_converter.ConverterInterface):
         'PReLU': ActivationType.PRELU,
         'TanH': ActivationType.TANH,
         'Sigmoid': ActivationType.SIGMOID,
+        'Clip': ActivationType.RELUX,
     }
 
     def __init__(self, option, src_model_file, src_weight_file):
@@ -177,6 +178,7 @@ class CaffeConverter(base_converter.ConverterInterface):
             'TanH': self.convert_activation,
             'Sigmoid': self.convert_activation,
             'PReLU': self.convert_activation,
+            'Clip': self.convert_activation,
             'Pooling': self.convert_pooling,
             'Concat': self.convert_concat,
             'Slice': self.convert_slice,
@@ -506,6 +508,13 @@ class CaffeConverter(base_converter.ConverterInterface):
 
             type_arg.s = six.b(ActivationType.LEAKYRELU.name)
 
+        if caffe_op.type == 'Clip':
+            mace_check(caffe_op.layer.clip_param.min == 0,
+                       "Mace only supports min == 0 Clip op")
+            limit_arg = op.arg.add()
+            limit_arg.name = MaceKeyword.mace_activation_max_limit_str
+            limit_arg.f = caffe_op.layer.clip_param.max
+
     def convert_folded_batchnorm(self, caffe_op):
         op = self.convert_general_op(caffe_op)
         op.type = MaceOp.BatchNorm.name