some ops not work. about tensorflow-nodejs

[yorkie]

Got the following error from gdb/lldb:

* thread #1: tid = 0xe373d, 0x0000000106e73cb1 libtensorflow.so`tensorflow::NodeBuilder::NodeOut::NodeOut(tensorflow::Node*, int) + 33, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x98)
  * frame #0: 0x0000000106e73cb1 libtensorflow.so`tensorflow::NodeBuilder::NodeOut::NodeOut(tensorflow::Node*, int) + 33
    frame #1: 0x0000000106e74e8d libtensorflow.so`void std::__1::vector<tensorflow::NodeBuilder::NodeOut, std::__1::allocator<tensorflow::NodeBuilder::NodeOut> >::__emplace_back_slow_path<tensorflow::Node* const&, int const&>(tensorflow::Node* const&&&, int const&&&) + 253
    frame #2: 0x0000000106e7420b libtensorflow.so`tensorflow::NodeBuilder::Input(tensorflow::Node*, int) + 91
    frame #3: 0x00000001022302a4 tensorflow.node`TensorflowNode::Operation::AddInput(info=0x00007fff5fbfe118) + 250 at operation.cc:245 [opt]
    frame #4: 0x000000010222c67c tensorflow.node`Nan::imp::FunctionCallbackWrapper(info=0x00007fff5fbfe190) + 137 at nan_callbacks_12_inl.h:174 [opt]
    frame #5: 0x000000010017b0c2 node`v8::internal::FunctionCallbackArguments::Call(void (*)(v8::FunctionCallbackInfo<v8::Value> const&)) + 466
    frame #6: 0x00000001001e6eef node`v8::internal::MaybeHandle<v8::internal::Object> v8::internal::(anonymous namespace)::HandleApiCallHelper<false>(v8::internal::Isolate*, v8::internal::Handle<v8::internal::HeapObject>, v8::internal::Handle<v8::internal::HeapObject>, v8::internal::Handle<v8::internal::FunctionTemplateInfo>, v8::internal::Handle<v8::internal::Object>, v8::internal::BuiltinArguments) + 911
    frame #7: 0x00000001001e6449 node`v8::internal::Builtin_Impl_HandleApiCall(v8::internal::BuiltinArguments, v8::internal::Isolate*) + 281

[yorkie]

Ah, this is because the all ops only can accept the Operation as its inputs except for graph.constant, passing a Tensor causes this problem @zihan-git

[yorkie]

BTW, may I ask you to fix this problem by checking the type of input and make always be an operation for ops like the following?

if (input instanceof tensorflow.Tensor) {
  input = this.constant(input);
}