GTSAM

Introduction

• Official tutorials: https://gtsam.org/tutorials/intro.html

• Example project that uses GTSAM: https://github.com/hanzheteng/LeGO-LOAM

Examples

Speed up Key operations by TBB library

// inference/Factor.h 
class Factor{
  protected:
    /// The keys involved in this factor
    KeyVector keys_;
}

// inference/Key.h
typedef FastVector<Key> KeyVector;

// base/types.h
typedef std::uint64_t Key;         /// Integer nonlinear key type
typedef std::uint64_t FactorIndex; /// Integer nonlinear factor index type
typedef ptrdiff_t DenseIndex;      /// The index type for Eigen objects

// base/FastVector.h
// FastVector is a type alias to a std::vector with a custom memory allocator.
// The particular allocator depends on GTSAM's cmake configuration.
template <typename T>
using FastVector =
    std::vector<T, typename internal::FastDefaultVectorAllocator<T>::type>;

// base/FastDefaultAllocator.h
/// Default allocator for vector types (we never use boost pool for vectors)
    template<typename T>
    struct FastDefaultVectorAllocator
    {
#if defined GTSAM_ALLOCATOR_TBB
      typedef tbb::tbb_allocator<T> type;
      static const bool isBoost = false;
      static const bool isTBB = true;
      static const bool isSTL = false;
#else
      typedef std::allocator<T> type;
      static const bool isBoost = false;
      static const bool isTBB = false;
      static const bool isSTL = true;
#endif
    };