add HgrToGraph tool

tools/CMakeLists.txt

@@ -10,6 +10,12 @@ target_link_libraries(GraphToHgr TBB::tbb TBB::tbbmalloc_proxy)
 set_property(TARGET GraphToHgr PROPERTY CXX_STANDARD 17)
 set_property(TARGET GraphToHgr PROPERTY CXX_STANDARD_REQUIRED ON)
 
+add_executable(HgrToGraph hgr_to_graph.cc)
+target_link_libraries(HgrToGraph ${Boost_LIBRARIES})
+target_link_libraries(HgrToGraph TBB::tbb TBB::tbbmalloc_proxy)
+set_property(TARGET HgrToGraph PROPERTY CXX_STANDARD 17)
+set_property(TARGET HgrToGraph PROPERTY CXX_STANDARD_REQUIRED ON)
+
 add_executable(HgrToParkway hgr_to_parkway_converter.cc)
 target_link_libraries(HgrToParkway ${Boost_LIBRARIES})
 target_link_libraries(HgrToParkway TBB::tbb TBB::tbbmalloc_proxy)
@@ -63,6 +69,7 @@ set_property(TARGET BenchShuffle PROPERTY CXX_STANDARD 17)
 set_property(TARGET BenchShuffle PROPERTY CXX_STANDARD_REQUIRED ON)
 
 set(TOOLS_TARGETS ${TOOLS_TARGETS} GraphToHgr
+                                   HgrToGraph
                                    EvaluateBipart
                                    VerifyPartition
                                    EvaluatePartition

tools/graph_to_hgr.cc

@@ -58,10 +58,6 @@ int main(int argc, char* argv[]) {
 
   std::ofstream out_stream(hgr_filename.c_str());
 
-  std::ifstream in_stream(graph_filename);
-  std::string line;
-  std::getline(in_stream, line);
-
   // Read Hypergraph
   HyperedgeID num_edges = 0;
   HypernodeID num_nodes = 0;
@@ -100,7 +96,6 @@ int main(int argc, char* argv[]) {
     out_stream << weight << std::endl;
   }
 
-  in_stream.close();
   out_stream.close();
 
   return 0;

tools/hgr_to_graph.cc

@@ -0,0 +1,121 @@
+/*******************************************************************************
+ * MIT License
+ *
+ * This file is part of Mt-KaHyPar.
+ *
+ * Copyright (C) 2020 Tobias Heuer <tobias.heuer@kit.edu>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ ******************************************************************************/
+
+#include <boost/program_options.hpp>
+
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <algorithm>
+
+#include "mt-kahypar/macros.h"
+#include "mt-kahypar/definitions.h"
+#include "mt-kahypar/io/hypergraph_factory.h"
+#include "mt-kahypar/io/hypergraph_io.h"
+
+using namespace mt_kahypar;
+namespace po = boost::program_options;
+
+int main(int argc, char* argv[]) {
+  std::string graph_filename;
+  std::string hgr_filename;
+
+  po::options_description options("Options");
+  options.add_options()
+    ("hypergraph,h",
+    po::value<std::string>(&hgr_filename)->value_name("<string>")->required(),
+    "Hypergraph filename")
+    ("graph,g",
+    po::value<std::string>(&graph_filename)->value_name("<string>")->required(),
+    "Graph filename");
+
+  po::variables_map cmd_vm;
+  po::store(po::parse_command_line(argc, argv, options), cmd_vm);
+  po::notify(cmd_vm);
+
+  std::ofstream out_stream(graph_filename.c_str());
+
+  // Read Hypergraph
+  HyperedgeID num_edges = 0;
+  HypernodeID num_nodes = 0;
+  HyperedgeID num_removed_single_pin_hyperedges = 0;
+  io::HyperedgeVector hyperedges;
+  vec<HyperedgeWeight> hyperedges_weight;
+  vec<HypernodeWeight> hypernodes_weight;
+
+  io::readHypergraphFile(hgr_filename, num_edges, num_nodes, num_removed_single_pin_hyperedges,
+                         hyperedges, hyperedges_weight, hypernodes_weight);
+  ALWAYS_ASSERT(hyperedges.size() == num_edges);
+  ALWAYS_ASSERT(num_removed_single_pin_hyperedges == 0);
+
+  // Write header
+  out_stream << num_nodes << " " << num_edges << " ";
+  if (hyperedges_weight.empty() && hypernodes_weight.empty()) {
+    out_stream << "0"  /* Unweighted */ << std::endl;
+  } else {
+    out_stream << (hypernodes_weight.empty() ? "0" : "1");
+    out_stream << (hyperedges_weight.empty() ? "0" : "1") << std::endl;
+  }
+
+  // insert backward edges
+  hyperedges.reserve(2 * num_edges);
+  for (size_t he = 0; he < num_edges; ++he) {
+    const auto& pins = hyperedges[he];
+    ALWAYS_ASSERT(pins.size() == 2, "Input hypergraph is not a graph!");
+    hyperedges.push_back({pins[1], pins[0]});
+  }
+
+  std::sort(hyperedges.begin(), hyperedges.end(),
+            [](const auto& l, const auto& r) { return l[0] < r[0] || (l[0] == r[0] && l[1] < r[1]); });
+
+  // Write edges
+  size_t i = 0;
+  bool at_start_of_line = true;
+  for (size_t he = 0; he < hyperedges.size();) {
+    const auto& pins = hyperedges[he];
+    if (!hypernodes_weight.empty() && at_start_of_line) {
+      out_stream << hypernodes_weight[i] << " ";
+    }
+    if (pins[0] == i) {
+      out_stream << (pins[1] + 1) << " ";
+      if (!hyperedges_weight.empty()) {
+        out_stream << hyperedges_weight[he] << " ";
+      }
+      ++he;
+      at_start_of_line = false;
+    } else {
+      out_stream << std::endl;
+      ++i;
+      ALWAYS_ASSERT(i < num_nodes);
+      at_start_of_line = true;
+    }
+  }
+
+  out_stream << std::endl;
+  out_stream.close();
+
+  return 0;
+}