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
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  //
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  #ifndef JACOBIAN_WORKSPACE_H
  #define JACOBIAN_WORKSPACE_H
  
  #include <Eigen/Core>
  #include <cassert>
  #include <vector>
  
  #include "g2o/core/eigen_types.h"
  #include "g2o_core_api.h"
  #include "hyper_graph.h"
  
  namespace g2o {
  
  struct OptimizableGraph;
  
  /**
   * \brief provide memory workspace for computing the Jacobians
   *
   * The workspace is used by an OptimizableGraph to provide temporary memory
   * for computing the Jacobian of the error functions.
   * Before calling linearizeOplus on an edge, the workspace needs to be allocated
   * by calling allocate().
   *
   * By default, the sizes are updated incrementally with each call. If the reset
   * flag is set to true, the counts are set back to
   */
  class G2O_CORE_API JacobianWorkspace {
   public:
    typedef std::vector<VectorX, Eigen::aligned_allocator<VectorX> >
        WorkspaceVector;
  
   public:
    JacobianWorkspace();
    ~JacobianWorkspace();
  
    /**
     * allocate the workspace
     */
    bool allocate();
  
    /**
     * update the maximum required workspace needed by taking into account this
     * edge
     */
    void updateSize(const HyperGraph::Edge* e, bool reset = false);
  
    /**
     * update the required workspace by looking at a full graph
     */
    void updateSize(const OptimizableGraph& graph, bool reset = false);
  
    /**
     * manually update with the given parameters
     */
    void updateSize(int numVertices, int dimension, bool reset = false);
  
    /**
     * set the full workspace to zero
     */
    void setZero();
  
    /**
     * return the workspace for a vertex in an edge
     */
    number_t* workspaceForVertex(int vertexIndex) {
      assert(vertexIndex >= 0 && (size_t)vertexIndex < _workspace.size() &&
             "Index out of bounds");
      return _workspace[vertexIndex].data();
    }
  
   protected:
    WorkspaceVector
        _workspace;  ///< the memory pre-allocated for computing the Jacobians
    int _maxNumVertices;  ///< the maximum number of vertices connected by a
                          ///< hyper-edge
    int _maxDimension;    ///< the maximum dimension (number of elements) for a
                          ///< Jacobian
  };
  
  }  // namespace g2o
  
  #endif
  