Don't swap src and dst when returning edge iterators (#184)

* Don't swap src and dst when returning edge iterators

* Remove ambiguous version of FindEdgeWithLabel

libgalois/include/katana/LC_CSR_CSC_Labeled_Graph.h

@@ -395,22 +395,6 @@ class LC_CSR_CSC_Labeled_Graph
     return FindFirstOrLastEdge<in_edges, opt>(begin, end, key);
   }
 
-  /**
-   * Returns an edge iterator to an edge from src to dst with some label. If not
-   * found, returns nothing.
-   */
-  std::optional<edge_iterator> FindEdgeWithLabel(
-      GraphNode src, GraphNode dst, const EdgeTy& data) const {
-    // trivial check; can't be connected if degree is 0
-    if (degrees_[src] == 0 || in_degrees_[dst] == 0) {
-      return std::nullopt;
-    }
-    if (degrees_[src] < in_degrees_[dst]) {
-      return FindEdgeWithLabel<false>(src, dst, data);
-    }
-    return FindEdgeWithLabel<true>(dst, src, data);
-  }
-
   /**
    * Returns an edge iterator to an edge with some node and key with some label
    * by searching for the key via the node's outgoing or incoming edges.
@@ -433,35 +417,20 @@ class LC_CSR_CSC_Labeled_Graph
    * nothing.
    */
   std::optional<edges_iterator> FindAllEdgesWithLabel(
-      GraphNode src, GraphNode dst, const EdgeTy& data) const {
+      GraphNode node, GraphNode key, const EdgeTy& data) const {
     // trivial check; can't be connected if degree is 0
-    if (degrees_[src] == 0 || in_degrees_[dst] == 0) {
+    if (degrees_[node] == 0 || in_degrees_[key] == 0) {
       return std::nullopt;
     }
-    if (degrees_[src] < in_degrees_[dst]) {
-      return FindAllEdgesWithLabel<false>(src, dst, data);
-    }
-
-    return FindAllEdgesWithLabel<true>(dst, src, data);
-  }
 
-  /**
-   * Returns all edges with some node and key with some label by searching for
-   * the key via the node's outgoing or incoming edges.  If not found, returns
-   * nothing.
-   */
-  template <bool in_edges>
-  std::optional<edges_iterator> FindAllEdgesWithLabel(
-      GraphNode node, GraphNode key, const EdgeTy& data) const {
     auto first = FindFirstOrLastEdgeWithLabel<
-        in_edges, FindEdgeWithLabelOptions::FindFirst>(node, key, data);
+        false, FindEdgeWithLabelOptions::FindFirst>(node, key, data);
     if (!first) {
       return std::nullopt;
     }
 
-    auto last =
-        FindFirstOrLastEdge<in_edges, FindEdgeWithLabelOptions::FindLast>(
-            std::get<1>(*first), std::get<2>(*first), key);
+    auto last = FindFirstOrLastEdge<false, FindEdgeWithLabelOptions::FindLast>(
+        std::get<1>(*first), std::get<2>(*first), key);
     KATANA_LOG_DEBUG_ASSERT(last);
 
     return internal::make_no_deref_range(
@@ -512,7 +481,14 @@ class LC_CSR_CSC_Labeled_Graph
    */
   bool IsConnectedWithEdgeLabel(
       GraphNode src, GraphNode dst, const EdgeTy& data) const {
-    return FindEdgeWithLabel(src, dst, data).has_value();
+    // trivial check; can't be connected if degree is 0
+    if (degrees_[src] == 0 || in_degrees_[dst] == 0) {
+      return false;
+    }
+    if (degrees_[src] < in_degrees_[dst]) {
+      return FindEdgeWithLabel<false>(src, dst, data).has_value();
+    }
+    return FindEdgeWithLabel<true>(dst, src, data).has_value();
   }
 
   /**