add hash function for tuple (#141)

nnvm/include/nnvm/base.h

@@ -7,6 +7,7 @@
 #define NNVM_BASE_H_
 
 #include <dmlc/base.h>
+#include <dmlc/common.h>
 #include <dmlc/any.h>
 #include <dmlc/memory.h>
 #include <dmlc/logging.h>

nnvm/include/nnvm/tuple.h

@@ -581,4 +581,34 @@ inline bool Tuple<ValueType>::Load(TStream *strm) {
 
 }  // namespace nnvm
 
+namespace std {
+/*! \brief hash function for Tuple. */
+template<typename T>
+struct hash<nnvm::Tuple<T> > {
+  /*! \brief hash a Tuple into unsigned int */
+  size_t operator()(const nnvm::Tuple<T>& val) const {
+    std::hash<uint32_t> hash_uint;
+    size_t res = hash_uint(val.ndim());
+    for (uint32_t i = 0; i < val.ndim(); ++i) {
+      res = dmlc::HashCombine(res, val[i]);
+    }
+    return res;
+  }
+};
+
+/*! \brief hash function for TShape. */
+template<>
+struct hash<nnvm::TShape> {
+  /*! \brief hash a TShape into unsigned int */
+  size_t operator()(const nnvm::TShape& val) const {
+    std::hash<uint32_t> hash_uint;
+    size_t res = hash_uint(val.ndim());
+    for (uint32_t i = 0; i < val.ndim(); ++i) {
+      res = dmlc::HashCombine(res, val[i]);
+    }
+    return res;
+  }
+};
+}  // namespace std
+
 #endif  // NNVM_TUPLE_H_