text: // g2o - General Graph Optimization
  // Copyright (C) 2011 R. Kuemmerle, G. Grisetti, W. Burgard
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  // * Redistributions of source code must retain the above copyright notice,
  //   this list of conditions and the following disclaimer.
  // * Redistributions in binary form must reproduce the above copyright
  //   notice, this list of conditions and the following disclaimer in the
  //   documentation and/or other materials provided with the distribution.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  // IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  // TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  // PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  // TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #ifndef G2O_OUTPUT_HELPER_H
  #define G2O_OUTPUT_HELPER_H
  
  #include <string>
  #include <iosfwd>
  #include "g2o/core/hyper_graph.h"
  #include "g2o_cli_api.h"
  
  namespace g2o {
  
    struct OptimizableGraph;
  
    /**
     * save the state of the optimizer into files for visualizing using Gnuplot
     */
    G2O_CLI_API bool saveGnuplot(const std::string& gnudump, const OptimizableGraph& optimizer);
    G2O_CLI_API bool saveGnuplot(const std::string& gnudump, const HyperGraph::VertexSet& vertices, const HyperGraph::EdgeSet& edges);
  
    /**
     * dump the edges to a stream, e.g., cout and redirect to gnuplot
     */
    G2O_CLI_API bool dumpEdges(std::ostream& os, const OptimizableGraph& optimizer);
  
  } // end namespace
  
  #endif
  