Merge pull request #77 from NervanaSystems/bob/tsort2

topological sort working with unit test

src/ngraph/node.cpp

@@ -25,7 +25,7 @@ ngraph::Node::Node(const std::vector<Node::ptr>& arguments, ValueType::ptr type)
     // Add this node as a user of each argument.
     for (auto node : m_arguments)
     {
-        node->m_users.insert(node.get());
+        node->m_users.insert(this);
     }
 }
 

src/ngraph/node.hpp

@@ -32,7 +32,7 @@ namespace ngraph
      ** zero or more nodes as arguments and one value, which is either a tensor
      ** view or a (possibly empty) tuple of values.
      **/
-    class Node : public TypedValueMixin
+    class Node : public TypedValueMixin, public std::enable_shared_from_this<Node>
     {
     public:
         using ptr = std::shared_ptr<Node>;
@@ -74,11 +74,11 @@ namespace ngraph
         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;
+        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/topological_sort.cpp

@@ -12,8 +12,53 @@
 // See the License for the specific language governing permissions and
 // ----------------------------------------------------------------------------
 
+#include "node.hpp"
 #include "topological_sort.hpp"
+#include "util.hpp"
 
-void ngraph::TopologicalSort::process(node_ptr node)
+using namespace ngraph;
+using namespace std;
+
+void ngraph::TopologicalSort::promote_node(Node* n)
+{
+    for (auto dn=m_dependent_nodes.begin(); dn!=m_dependent_nodes.end(); dn++)
+    {
+        if (dn->first > 0)   // Skip zero as they should never be promoted
+        {
+            auto it = find(dn->second.begin(), dn->second.end(), n);
+            if (it != dn->second.end())
+            {
+                // found the node
+                dn->second.erase(it);
+                m_dependent_nodes[dn->first-1].push_back(n);
+            }
+        }
+    }
+}
+
+void ngraph::TopologicalSort::process(node_ptr p)
+{
+    traverse_nodes(p, [&](node_ptr node)
+    {
+        list<Node*>& node_list = m_dependent_nodes[node->arguments().size()];
+        node_list.push_back(node.get());
+    });
+
+    list<Node*>& independent_nodes = m_dependent_nodes[0];
+    while (independent_nodes.size() > 0)
+    {
+        auto independent_node = independent_nodes.front();
+        m_sorted_list.push_back(independent_node);
+        independent_nodes.pop_front();
+
+        for (auto user : independent_node->users())
+        {
+            promote_node(user);
+        }
+    }
+}
+
+const std::vector<Node*>& ngraph::TopologicalSort::get_sorted_list() const
 {
+    return m_sorted_list;
 }

src/ngraph/topological_sort.hpp

@@ -15,6 +15,8 @@
 #pragma once
 
 #include <memory>
+#include <map>
+#include <list>
 
 namespace ngraph
 {
@@ -26,9 +28,14 @@ namespace ngraph
 class ngraph::TopologicalSort
 {
 public:
-    TopologicalSort();
+    TopologicalSort() {}
 
-    static void process(node_ptr);
+    void process(node_ptr);
+    const std::vector<Node*>& get_sorted_list() const;
 
 private:
+    void promote_node(Node* n);
+
+    std::map<size_t, std::list<Node*>> m_dependent_nodes;
+    std::vector<Node*>                 m_sorted_list;
 };

src/ngraph/type.hpp

@@ -40,7 +40,7 @@ namespace ngraph
 
         virtual ~ValueType() {}
         virtual bool operator==(const ValueType::ptr& that) const = 0;
-        bool         operator!=(const ValueType::ptr& that) const { return !(*this == that); }
+        bool operator!=(const ValueType::ptr& that) const { return !(*this == that); }
     };
 
     /**
@@ -140,6 +140,7 @@ namespace ngraph
          ** The type associated with this value.
          **/
         const ValueType::ptr type() const { return m_type; }
+
     protected:
         ValueType::ptr m_type;
     };

test/topological_sort.cpp

@@ -26,28 +26,74 @@
 using namespace std;
 using namespace ngraph;
 
-TEST(top_sort, basic)
+static bool validate_list(const vector<Node*>& nodes)
 {
-    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);
+    bool rc = true;
+    for (auto it=nodes.rbegin(); it!=nodes.rend(); it++)
+    {
+        Node* node = *it;
+        auto node_tmp = *it;
+        auto dependencies_tmp = node_tmp->arguments();
+        vector<Node*> dependencies;
+        for (shared_ptr<Node> n : dependencies_tmp)
+        {
+            dependencies.push_back(n.get());
+        }
+        auto tmp = it+1;
+        for (; tmp!=nodes.rend(); tmp++)
+        {
+            auto dep_tmp = *tmp;
+            auto found = find(dependencies.begin(), dependencies.end(), dep_tmp);
+            if (found != dependencies.end())
+            {
+                dependencies.erase(found);
+            }
+        }
+        if (dependencies.size() > 0)
+        {
+            rc = false;
+        }
+    }
+    return rc;
+}
+
+TEST(topological_sort, basic)
+{
+    vector<shared_ptr<Parameter>> args;
+    for (int i=0; i<10; i++)
+    {
+        auto arg = op::parameter(element::Float::type, {1});
+        ASSERT_NE(nullptr, arg);
+        args.push_back(arg);
+    }
+
+    auto t0 = op::add(args[0], args[1]);
     ASSERT_NE(nullptr, t0);
-    auto t1 = op::add(arg0, arg1);
+    auto t1 = op::dot(t0, args[2]);
     ASSERT_NE(nullptr, t1);
-    Node::ptr r0 = op::add(t0, t1);
+    auto t2 = op::multiply(t0, args[3]);
+    ASSERT_NE(nullptr, t2);
+
+    auto t3 = op::add(t1, args[4]);
+    ASSERT_NE(nullptr, t2);
+    auto t4 = op::add(t2, args[5]);
+    ASSERT_NE(nullptr, t3);
+
+    Node::ptr r0 = op::add(t3, t4);
     ASSERT_NE(nullptr, r0);
 
-    auto f0 = op::function(r0, {arg0, arg1});
+    auto f0 = op::function(r0, args);
     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);
+    TopologicalSort ts;
+    ts.process(r0);
+    auto sorted_list = ts.get_sorted_list();
+
+    EXPECT_TRUE(validate_list(sorted_list));
 }