Add topological sort and viualization classes

src/CMakeLists.txt

@@ -29,6 +29,9 @@ set (SRC
     ops/tuple.cpp
     types/element_type.cpp
     types/type.cpp
+    ngraph/node.cpp
+    ngraph/topological_sort.cpp
+    ngraph/visualize.cpp
 )
 
 # NOTE: We'd prefer to only have the .cpp files *in* the 'transformers' directory be compiled

src/log.hpp

@@ -36,8 +36,7 @@ namespace nervana
             return i < _size ? _string[i] : throw std::out_of_range("");
         }
         constexpr const char* get_ptr(size_t offset) const { return &_string[offset]; }
-        constexpr size_t      size() const { return _size; }
-
+        constexpr size_t                     size() const { return _size; }
     private:
         const char* _string;
         size_t      _size;
@@ -45,9 +44,8 @@ namespace nervana
 
     constexpr const char* find_last(conststring s, size_t offset, char ch)
     {
-        return offset == 0
-                   ? s.get_ptr(0)
-                   : (s[offset] == ch ? s.get_ptr(offset + 1) : find_last(s, offset - 1, ch));
+        return offset == 0 ? s.get_ptr(0) : (s[offset] == ch ? s.get_ptr(offset + 1)
+                                                             : find_last(s, offset - 1, ch));
     }
 
     constexpr const char* find_last(conststring s, char ch)
@@ -69,7 +67,6 @@ namespace nervana
         ~log_helper();
 
         std::ostream& stream() { return _stream; }
-
     private:
         std::stringstream _stream;
     };
@@ -84,9 +81,9 @@ namespace nervana
         static void stop();
 
     private:
-        static void                    log_item(const std::string& s);
-        static void                    process_event(const std::string& s);
-        static void                    thread_entry(void* param);
+        static void log_item(const std::string& s);
+        static void process_event(const std::string& s);
+        static void thread_entry(void* param);
         static std::string             log_path;
         static std::deque<std::string> queue;
     };

src/ngraph/element_type.hpp

@@ -41,13 +41,12 @@ namespace ngraph
 
             bool operator==(const Type& other) const;
             bool operator!=(const Type& other) const { return !(*this == other); }
-
         private:
             static std::map<std::string, Type> m_element_list;
-            size_t                             m_bitwidth;
-            bool                               m_is_float;
-            bool                               m_is_signed;
-            const std::string                  m_cname;
+            size_t            m_bitwidth;
+            bool              m_is_float;
+            bool              m_is_signed;
+            const std::string m_cname;
         };
 
         // Literals (and probably other things we don't know about yet) need to have their C++ types

src/ngraph/function.hpp

@@ -30,12 +30,9 @@ namespace ngraph
         Function(const Node::ptr&                               result,
                  const std::vector<std::shared_ptr<Parameter>>& parameters);
 
-        Node::ptr result() { return m_result; }
-
+        Node::ptr      result() { return m_result; }
         Parameter::ptr parameter(size_t i) { return m_parameters[i]; }
-
-        std::string name() const { return m_name; }
-
+        std::string                     name() const { return m_name; }
     protected:
         Node::ptr                                       m_result;
         std::vector<std::shared_ptr<ngraph::Parameter>> m_parameters;

src/ngraph/node.cpp

+// ----------------------------------------------------------------------------
+// Copyright 2017 Nervana Systems Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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
+// ----------------------------------------------------------------------------
+
+#include "node.hpp"
+#include "op.hpp"
+
+size_t ngraph::Node::m_next_instance_id = 0;
+
+ngraph::Node::Node(const std::vector<Node::ptr>& arguments, ValueType::ptr type)
+    : TypedValueMixin(type)
+    , m_arguments(arguments)
+    , m_instance_id(m_next_instance_id++)
+{
+    // Add this node as a user of each argument.
+    for (auto node : m_arguments)
+    {
+        node->m_users.insert(node.get());
+    }
+}
+
+bool ngraph::Node::is_op() const
+{
+    return dynamic_cast<const ngraph::Op*>(this) != nullptr;
+}
+
+bool ngraph::Node::is_parameter() const
+{
+    return dynamic_cast<const ngraph::Parameter*>(this) != nullptr;
+}
+
+std::ostream& ngraph::operator<<(std::ostream& out, const ngraph::Node& node)
+{
+    auto op_tmp        = dynamic_cast<const ngraph::Op*>(&node);
+    auto parameter_tmp = dynamic_cast<const ngraph::Op*>(&node);
+    if (op_tmp)
+    {
+        out << "Op(" << op_tmp->node_id() << ")";
+    }
+    else if (parameter_tmp)
+    {
+        out << "Parameter(" << parameter_tmp->node_id() << ")";
+    }
+    else
+    {
+        out << "Node(" << node.node_id() << ")";
+    }
+    return out;
+}

src/ngraph/node.hpp

@@ -38,19 +38,9 @@ namespace ngraph
         using ptr = std::shared_ptr<Node>;
 
     protected:
-        Node(const Nodes& arguments, ValueType::ptr type = nullptr)
-            : TypedValueMixin(type)
-            , m_arguments(arguments)
-        {
-            // Add this node as a user of each argument.
-            for (auto node : m_arguments)
-            {
-                node->m_users.insert(node.get());
-            }
-        }
+        Node(const Nodes& arguments, ValueType::ptr type = nullptr);
 
         virtual ~Node() {}
-
     public:
         /// A "one-liner" describing this node.
         virtual std::string description() const = 0;
@@ -65,6 +55,8 @@ namespace ngraph
         std::string name() const { return m_name; }
         void        name(const std::string& name) { m_name = name; }
 
+        virtual std::string node_id() const = 0;
+
         /**
          ** Return true if this has the same implementing class as node. This
          ** will be used by the pattern matcher when comparing a pattern
@@ -75,9 +67,19 @@ namespace ngraph
             return typeid(*this) == typeid(*node.get());
         }
 
+        bool is_op() const;
+        bool is_parameter() const;
+
+        size_t               instance_id() const { return m_instance_id; }
+        friend std::ostream& operator<<(std::ostream&, const Node&);
+
     protected:
         Nodes m_arguments;
         std::multiset<Node*>   m_users;
         std::string            m_name;
+        size_t                 m_instance_id;
+        static size_t          m_next_instance_id;
     };
+
+    using node_ptr = std::shared_ptr<Node>;
 }

src/ngraph/op.hpp

@@ -72,6 +72,9 @@ namespace ngraph
             : Node(arguments, nullptr)
         {
         }
+
+        virtual std::string op_class_name() const = 0;
+        virtual std::string node_id() const;
     };
 
     /**
@@ -81,7 +84,6 @@ namespace ngraph
     class FunctionOp : public Op
     {
         virtual std::string description() const override { return "FunctionOp"; }
-
     protected:
         Node::ptr m_function;
     };
@@ -95,11 +97,9 @@ namespace ngraph
     public:
         virtual std::string description() const override { return "BuiltinOp"; }
         /// Name of the builtin op, for debugging and logging.
-        virtual std::string op_name() const = 0;
 
         // TODO: Implement for each op. This enables graphs to be built for now.
         virtual void propagate_types() override {}
-
     protected:
         BuiltinOp(const std::vector<Node::ptr>& args)
             : Op(args)
@@ -115,7 +115,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "abs"; }
+        virtual std::string op_class_name() const override { return "abs"; }
         //virtual void propagate_types() override;
     };
 
@@ -126,7 +126,7 @@ namespace ngraph
             : BuiltinOp({arg0, arg1})
         {
         }
-        virtual std::string op_name() const override { return "add"; }
+        virtual std::string op_class_name() const override { return "add"; }
         //virtual void propagate_types() override;
     };
 
@@ -138,7 +138,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "ceiling"; }
+        virtual std::string op_class_name() const override { return "ceiling"; }
         //virtual void propagate_types() override;
     };
 
@@ -150,7 +150,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "divide"; }
+        virtual std::string op_class_name() const override { return "divide"; }
         //virtual void propagate_types() override;
     };
 
@@ -162,7 +162,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "equal"; }
+        virtual std::string op_class_name() const override { return "equal"; }
         //virtual void propagate_types() override;
     };
 
@@ -174,7 +174,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "exp"; }
+        virtual std::string op_class_name() const override { return "exp"; }
         //virtual void propagate_types() override;
     };
 
@@ -186,7 +186,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "floor"; }
+        virtual std::string op_class_name() const override { return "floor"; }
         //virtual void propagate_types() override;
     };
 
@@ -198,7 +198,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "greater"; }
+        virtual std::string op_class_name() const override { return "greater"; }
         //virtual void propagate_types() override;
     };
 
@@ -210,7 +210,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "less"; }
+        virtual std::string op_class_name() const override { return "less"; }
         //virtual void propagate_types() override;
     };
 
@@ -222,7 +222,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "log"; }
+        virtual std::string op_class_name() const override { return "log"; }
         //virtual void propagate_types() override;
     };
 
@@ -234,7 +234,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "max"; }
+        virtual std::string op_class_name() const override { return "max"; }
         //virtual void propagate_types() override;
     };
 
@@ -246,7 +246,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "min"; }
+        virtual std::string op_class_name() const override { return "min"; }
         //virtual void propagate_types() override;
     };
 
@@ -258,7 +258,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "multiply"; }
+        virtual std::string op_class_name() const override { return "multiply"; }
         //virtual void propagate_types() override;
     };
 
@@ -270,7 +270,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "negate"; }
+        virtual std::string op_class_name() const override { return "negate"; }
         //virtual void propagate_types() override;
     };
 
@@ -282,7 +282,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "power"; }
+        virtual std::string op_class_name() const override { return "power"; }
         //virtual void propagate_types() override;
     };
 
@@ -294,7 +294,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "remainder"; }
+        virtual std::string op_class_name() const override { return "remainder"; }
         //virtual void propagate_types() override;
     };
 
@@ -307,7 +307,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "reshape"; }
+        virtual std::string op_class_name() const override { return "reshape"; }
         //virtual void propagate_types() override;
     protected:
         Shape m_shape;
@@ -321,7 +321,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "subtract"; }
+        virtual std::string op_class_name() const override { return "subtract"; }
         //virtual void propagate_types() override;
     };
 }

src/ngraph/ops/broadcast.hpp

@@ -34,7 +34,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "broadcast"; }
+        virtual std::string op_class_name() const override { return "broadcast"; }
         virtual void        propagate_types() override;
 
     protected:

src/ngraph/ops/concatenate.hpp

@@ -29,7 +29,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "concatenate"; }
+        virtual std::string op_class_name() const override { return "concatenate"; }
         virtual void        propagate_types() override;
     };
 }

src/ngraph/ops/constant.hpp

@@ -14,6 +14,8 @@
 
 #pragma once
 
+#include <sstream>
+
 #include "../element_type.hpp"
 
 namespace ngraph
@@ -48,7 +50,13 @@ namespace ngraph
         }
 
         virtual std::string description() const override { return "ConstantScalar"; }
-
+        virtual std::string node_id() const override
+        {
+            std::stringstream ss;
+            ss << description() << "_" << node_id();
+            return ss.str();
+        }
+                
         typename T::ctype value() const { return m_value; }
 
         // Make a constant from any value that can be converted to the C++ type we use

src/ngraph/ops/convert.hpp

@@ -26,7 +26,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "convert"; }
+        virtual std::string op_class_name() const override { return "convert"; }
         virtual void        propagate_types() override;
     protected:
         const ngraph::element::Type& m_element_type;

src/ngraph/ops/dot.hpp

@@ -25,7 +25,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "dot"; }
+        virtual std::string op_class_name() const override { return "dot"; }
         virtual void        propagate_types() override;
     };
 

src/ngraph/ops/parameter.hpp

@@ -38,9 +38,9 @@ namespace ngraph
     public:
         Parameter(const ValueType::ptr& value_type);
 
-        std::string description() const override { return "Parameter"; }
-
-        virtual void propagate_types() override;
+        std::string         description() const override { return "Parameter"; }
+        virtual void        propagate_types() override;
+        virtual std::string node_id() const override;
 
     protected:
         Function* m_function;

src/ngraph/ops/tuple.hpp

@@ -29,7 +29,7 @@ namespace ngraph
         {
         }
 
-        virtual std::string op_name() const override { return "tuple"; }
+        virtual std::string op_class_name() const override { return "tuple"; }
         virtual void        propagate_types() override;
     };
 }

src/ngraph/shape.hpp

@@ -41,10 +41,8 @@ namespace ngraph
          ** Conversion to a vector of sizes.
          **/
         operator const std::vector<size_t>&() const { return m_sizes; }
-
         bool operator==(const Shape& shape) const { return m_sizes == shape.m_sizes; }
         bool operator!=(const Shape& shape) const { return m_sizes != shape.m_sizes; }
-
     protected:
         std::vector<size_t> m_sizes;
     };

src/ngraph/topological_sort.cpp

+// ----------------------------------------------------------------------------
+// Copyright 2017 Nervana Systems Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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
+// ----------------------------------------------------------------------------
+
+#include "topological_sort.hpp"
+
+void ngraph::TopologicalSort::process(node_ptr node)
+{
+}

src/ngraph/topological_sort.hpp

+// ----------------------------------------------------------------------------
+// Copyright 2017 Nervana Systems Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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
+// ----------------------------------------------------------------------------
+
+#pragma once
+
+#include <memory>
+
+namespace ngraph
+{
+    class TopologicalSort;
+    class Node;
+    using node_ptr = std::shared_ptr<Node>;
+}
+
+class ngraph::TopologicalSort
+{
+public:
+    TopologicalSort();
+
+    static void process(node_ptr);
+
+private:
+};

src/ngraph/type.hpp

@@ -89,7 +89,6 @@ namespace ngraph
          ** Construct empty tuple and add value types later.
          **/
         TupleType() {}
-
         /**
          ** /param element_types A vector of types for the tuple elements
          **/
@@ -123,7 +122,6 @@ namespace ngraph
          ** /param type The new type
          **/
         void type(const ValueType::ptr& type) { m_type = type; }
-
         /**
          ** Set the type to be a tensor view type
          ** /param element_type The type of the tensor elements
@@ -138,12 +136,10 @@ namespace ngraph
          ** The type associated with this value.
          **/
         ValueType::ptr type() { return m_type; }
-
         /**
          ** The type associated with this value.
          **/
         const ValueType::ptr type() const { return m_type; }
-
     protected:
         ValueType::ptr m_type;
     };

src/ngraph/visualize.cpp

+// ----------------------------------------------------------------------------
+// Copyright 2017 Nervana Systems Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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
+// ----------------------------------------------------------------------------
+
+#include <list>
+#include <fstream>
+#include <cstdio>
+
+#include "visualize.hpp"
+#include "ngraph/node.hpp"
+#include "util.hpp"
+
+using namespace ngraph;
+using namespace std;
+
+Visualize::Visualize(const string& name)
+    : m_name{name}
+{
+}
+
+void Visualize::add(node_ptr p)
+{
+    // map<size_t, list<node_ptr>> dependent_nodes;
+    traverse_nodes(p, [&](node_ptr node)
+    {
+        for (auto arg : node->arguments())
+        {
+            m_ss << "    " << arg->node_id() << " -> " << node->node_id() << ";\n";
+        }
+    });
+}
+
+void Visualize::save_dot(const string& path) const
+{
+    auto tmp_file = path+".tmp";
+    ofstream out(tmp_file);
+    if (out)
+    {
+        out << "digraph " << m_name << "\n{\n";
+        out << m_ss.str();
+        out << "}\n";
+        out.close();
+
+        stringstream ss;
+        ss << "dot -Tpng " << tmp_file << " -o " << path;
+        auto cmd = ss.str();
+        auto stream = popen(cmd.c_str(), "r");
+        pclose(stream);
+
+        // remove(tmp_file.c_str());
+    }
+}

src/ngraph/visualize.hpp

+// ----------------------------------------------------------------------------
+// Copyright 2017 Nervana Systems Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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
+// ----------------------------------------------------------------------------
+
+#pragma once
+
+#include <functional>
+#include <memory>
+#include <set>
+#include <sstream>
+
+namespace ngraph
+{
+    class Visualize;
+    class Node;
+    using node_ptr = std::shared_ptr<Node>;
+}
+
+class ngraph::Visualize
+{
+public:
+    Visualize(const std::string& name = "ngraph");
+
+    void add(node_ptr);
+
+    void save_dot(const std::string& path) const;
+
+private:
+    std::stringstream m_ss;
+    std::string       m_name;
+};

src/ops/op.cpp

@@ -13,12 +13,20 @@
 // ----------------------------------------------------------------------------
 
 #include <algorithm>
+#include <sstream>
 
 #include "ngraph/ngraph.hpp"
 
 using namespace ngraph;
 using namespace std;
 
+std::string ngraph::Op::node_id() const
+{
+    stringstream ss;
+    ss << op_class_name() << "_" << m_instance_id;
+    return ss.str();
+}
+
 Node::ptr ngraph::op::abs(const Node::ptr& arg)
 {
     return make_shared<AbsOp>(arg);

src/ops/parameter.cpp

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // ----------------------------------------------------------------------------
 
+#include <sstream>
+
 #include "ngraph/ngraph.hpp"
 
 using namespace std;
@@ -34,7 +36,9 @@ void Parameter::assign_function(Function* function, size_t index)
     m_index    = index;
 }
 
-void Parameter::propagate_types() {}
+void Parameter::propagate_types()
+{
+}
 
 shared_ptr<Parameter> ngraph::op::parameter(const ValueType::ptr& value_type)
 {
@@ -46,3 +50,10 @@ shared_ptr<Parameter> ngraph::op::parameter(const ngraph::element::Type element_
 {
     return make_shared<Parameter>(make_shared<TensorViewType>(element_type, shape));
 }
+
+std::string ngraph::Parameter::node_id() const
+{
+    stringstream ss;
+    ss << "parameter_" << m_instance_id;
+    return ss.str();
+}

src/tree.hpp

@@ -51,7 +51,7 @@ public:
     bool                     is_list() const { return m_is_list; }
     T                        get_value() const { return m_value; }
     const std::vector<tree>& get_list() const { return m_list; }
-    static void              traverse_tree(tree& s, std::function<void(T*)> func)
+    static void traverse_tree(tree& s, std::function<void(T*)> func)
     {
         if (s.is_list())
         {

src/util.cpp

@@ -16,6 +16,7 @@
 #include <map>
 
 #include "util.hpp"
+#include "ngraph/node.hpp"
 
 using namespace std;
 
@@ -129,3 +130,25 @@ size_t ngraph::hash_combine(const std::vector<size_t>& list)
     }
     return seed;
 }
+
+static void traverse_nodes(std::shared_ptr<ngraph::Node>                      p,
+                           std::function<void(std::shared_ptr<ngraph::Node>)> f,
+                           std::set<size_t>&                                  instances_seen)
+{
+    f(p);
+    for (auto arg : p->arguments())
+    {
+        if (instances_seen.find(arg->instance_id()) == instances_seen.end())
+        {
+            instances_seen.insert(arg->instance_id());
+            traverse_nodes(arg, f, instances_seen);
+        }
+    }
+}
+
+void ngraph::traverse_nodes(std::shared_ptr<ngraph::Node>                      p,
+                            std::function<void(std::shared_ptr<ngraph::Node>)> f)
+{
+    std::set<size_t> instances_seen;
+    ::traverse_nodes(p, f, instances_seen);
+}

src/util.hpp

@@ -24,11 +24,12 @@
 
 namespace ngraph
 {
+    class Node;
     class stopwatch;
     extern std::map<std::string, stopwatch*> stopwatch_statistics;
 
     template <typename T>
-    std::string join(const T& v, const std::string& sep)
+    std::string join(const T& v, const std::string& sep = ", ")
     {
         std::ostringstream ss;
         for (const auto& x : v)
@@ -83,10 +84,10 @@ namespace ngraph
     }
 
     size_t hash_combine(const std::vector<size_t>& list);
-    void   dump(std::ostream& out, const void*, size_t);
+    void dump(std::ostream& out, const void*, size_t);
 
-    std::string              to_lower(const std::string& s);
-    std::string              trim(const std::string& s);
+    std::string to_lower(const std::string& s);
+    std::string trim(const std::string& s);
     std::vector<std::string> split(const std::string& s, char delimiter, bool trim = false);
 
     class stopwatch
@@ -148,7 +149,6 @@ namespace ngraph
         size_t get_total_milliseconds() const { return get_total_nanoseconds() / 1e6; }
         size_t get_total_microseconds() const { return get_total_nanoseconds() / 1e3; }
         size_t get_total_nanoseconds() const { return m_total_time.count(); }
-
     private:
         std::chrono::high_resolution_clock                          m_clock;
         std::chrono::time_point<std::chrono::high_resolution_clock> m_start_time;
@@ -194,4 +194,5 @@ namespace ngraph
         return a * b;
     }
 
+    void traverse_nodes(std::shared_ptr<Node> p, std::function<void(std::shared_ptr<Node>)> f);
 } // end namespace ngraph

src/uuid.hpp

@@ -73,7 +73,7 @@ public:
         return memcmp((char*)m_data, (char*)other.m_data, 16) == 0;
     }
 
-    bool                 operator!=(const uuid_type& other) const { return !(*this == other); }
+    bool operator!=(const uuid_type& other) const { return !(*this == other); }
     friend std::ostream& operator<<(std::ostream& out, const uuid_type& id)
     {
         out << id.to_string();

test/CMakeLists.txt

@@ -27,6 +27,8 @@ set (SRC
     tensor.cpp
     element_type.cpp
     uuid.cpp
+    topological_sort.cpp
+    op.cpp
 )
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

test/build_graph.cpp

@@ -28,6 +28,7 @@ TEST(build_graph, build_simple)
     auto arg3        = op::parameter(element::Float::type, {32, 7});
     auto broadcast_1 = op::broadcast(arg3, {10, 32, 7}, {0});
     auto dot         = op::dot(arg2, arg0);
+    ASSERT_EQ(2, dot->arguments().size());
     ASSERT_EQ(dot->arguments()[0], arg2);
     ASSERT_EQ(dot->arguments()[1], arg0);
 
@@ -96,4 +97,6 @@ TEST(build_graph, literal)
 }
 
 // Check argument inverses
-TEST(build_graph, arg_inverse) {}
+TEST(build_graph, arg_inverse)
+{
+}

test/ngraph.cpp

@@ -12,15 +12,15 @@
 // See the License for the specific language governing permissions and
 // ----------------------------------------------------------------------------
 
-#include <vector>
-#include <string>
-#include <sstream>
-#include <memory>
 #include <dlfcn.h>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
 
 #include "gtest/gtest.h"
-#include "ngraph.hpp"
 #include "log.hpp"
+#include "ngraph.hpp"
 
 using namespace std;
 

test/op.cpp

+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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
+// ----------------------------------------------------------------------------
+
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+#include "ngraph/ngraph.hpp"
+
+using namespace std;
+using namespace ngraph;
+
+TEST(op, is_op)
+{
+    auto arg0 = op::parameter(element::Float::type, {1});
+    ASSERT_NE(nullptr, arg0);
+    EXPECT_TRUE(arg0->is_parameter());
+    EXPECT_FALSE(arg0->is_op());
+}
+
+TEST(op, is_parameter)
+{
+    auto arg0 = op::parameter(element::Float::type, {1});
+    ASSERT_NE(nullptr, arg0);
+    auto t0 = op::add(arg0, arg0);
+    ASSERT_NE(nullptr, t0);
+    EXPECT_FALSE(t0->is_parameter());
+    EXPECT_TRUE(t0->is_op());
+}

test/topological_sort.cpp

+// ----------------------------------------------------------------------------
+// Copyright 2017 Nervana Systems Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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
+// ----------------------------------------------------------------------------
+
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+#include "ngraph/ngraph.hpp"
+#include "ngraph/topological_sort.hpp"
+#include "ngraph/visualize.hpp"
+
+using namespace std;
+using namespace ngraph;
+
+TEST(top_sort, basic)
+{
+    auto arg0 = op::parameter(element::Float::type, {1});
+    ASSERT_NE(nullptr, arg0);
+    auto arg1 = op::parameter(element::Float::type, {1});
+    ASSERT_NE(nullptr, arg1);
+    auto t0 = op::add(arg0, arg1);
+    ASSERT_NE(nullptr, t0);
+    auto t1 = op::add(arg0, arg1);
+    ASSERT_NE(nullptr, t1);
+    Node::ptr r0 = op::add(t0, t1);
+    ASSERT_NE(nullptr, r0);
+
+    auto f0 = op::function(r0, {arg0, arg1});
+    ASSERT_NE(nullptr, f0);
+
+    ASSERT_EQ(2, r0->arguments().size());
+    auto op_r0 = static_pointer_cast<Op>(r0);
+    cout << "op_r0 name " << *r0 << endl;
+
+    Visualize vz;
+    vz.add(r0);
+    vz.save_dot("test.png");
+    TopologicalSort::process(r0);
+}