Add PReLU support to mxnet frontend (#1249)

nnvm/python/nnvm/frontend/mxnet.py

@@ -151,9 +151,10 @@ def _dropout(inputs, attrs):
 
 def _leaky_relu(inputs, attrs):
     act_type = _required_attr(attrs, 'act_type')
-    if act_type in ['leaky']:
-        op_name, new_attrs = 'leaky_relu', {}
-        new_attrs['alpha'] = attrs.get('slope', 0.25)
+    if act_type in ['leaky', 'prelu']:
+        op_name, new_attrs = act_type, {}
+        if act_type == 'leaky':
+            new_attrs['alpha'] = attrs.get('slope', 0.25)
         sym = _get_nnvm_op(op_name)(*inputs, **new_attrs)
     elif act_type == 'elu':
         slope = attrs.get('slope', 0.25)

nnvm/tests/python/frontend/mxnet/test_forward.py

@@ -97,6 +97,13 @@ def test_forward_rrelu():
     mx_sym = mx.sym.LeakyReLU(data, act_type='rrelu', lower_bound=0.3, upper_bound=0.7)
     verify_mxnet_frontend_impl(mx_sym, (1, 3, 100, 100), (1, 6, 100, 100))
 
+def test_forward_prelu():
+    data = mx.sym.var('data')
+    data = mx.sym.concat(data, -data, dim=1)  # negative part explicitly
+    gamma = mx.sym.zeros(shape=(6,))
+    mx_sym = mx.sym.LeakyReLU(data, gamma=gamma, act_type='prelu')
+    verify_mxnet_frontend_impl(mx_sym, (1, 3, 100, 100), (1, 6, 100, 100))
+
 def test_forward_softrelu():
     data = mx.sym.var('data')
     data = mx.sym.concat(data, -data, dim=1)  # negative part explicitly
@@ -126,6 +133,7 @@ if __name__ == '__main__':
     test_forward_resnet()
     test_forward_elu()
     test_forward_rrelu()
+    test_forward_prelu()
     test_forward_softrelu()
     test_forward_fc_flatten()
     test_forward_clip()