How to transfer a vector to the constructor of an observation observer with axial motion so that it can be read inside the functor

Question

I am expanding the example of studying parameters from boost odeint used with traction, and I don’t know how to pass the vector of values ​​to the observer constructor, so that these values ​​can be accessed (read-only) from within the observer functor.

The following code is for observer only.

//// Observes the system, comparing the current state to 
//// values in unchangingVector

struct minimum_perturbation_observer { 
  struct minPerturbFunctor
  {
    template< class T >
    __host__ __device__
    void operator()( T t ) const
    {
    //// I would like to be able to read any member 
    //// of m_unchangingVector here.
    }
  };


  // CONSTRUCTOR
  minimum_perturbation_observer( size_t N, state_type unchangingVector, int len) : 
        m_N( N ),
        m_output( N ),
        m_unchangingVector( len ) // len is the correct length of unchangingVector
  {
    // all trials start with output = 0
    thrust::fill( m_output.begin() , m_output.end() , 0.0 );

    // copy unchangingVector to m_unchangingVector, the latter 
    // of which should be accessible from the functor operator() 
    // above.
    thrust::copy( unchangingVector.begin(), unchangingVector.end(),
                  m_unchangingVector.begin());
  }

  template< class State >
  void operator()(State x , value_type t )
  {
    thrust::for_each(
                 thrust::make_zip_iterator( thrust::make_tuple(
                                   boost::begin( x ) + 0*m_N,
                                   boost::begin( x ) + 1*m_N,
                                   boost::begin( m_output )
                                   )
                            ),
                 thrust::make_zip_iterator( thrust::make_tuple(
                                   boost::begin( x ) + 1*m_N,
                                   boost::begin( x ) + 2*m_N,
                                   boost::begin( m_output ) + m_N
                                       )
                            ) ,
                 minPerturbFunctor() );
  }

  // variables
  size_t m_N; // number of trials (i.e. number of initial conditions)
  state_type m_output;   // of length N_ICS
  state_type m_unchangingVector; // 
};

I experimented with creating m_unchangingVector staticor const, but this is not true because it needs to be installed after creating the observer instance.

, , - unchangingVector thrust::make_zip_iterator( thrust::make_tuple(..., , , ( ). , , , (T t) , unchangingVector , .

, , , , , /.

, , error: a nonstatic member reference must be relative to a specific object. , m_unchangingVector .

---

, , , .

.

  struct minPerturbFunctor
  {

    minPerturbFunctor( state_type unchangingVector, int len ) :
    f_unchangingVector( len ) 
    {
      // copy from argument to local vector (probably unnecessary, but
      // getting errors about calling host-functions from device/host 
      // so being paranoid about trying to make sure things are device-side
      thrust::copy( f_unchangingVector.begin(), 
                    f_unchangingVector.end(), 
                    unchangingVector.begin());
      f_len = len;      
    };

    template< class T >
    __host__ __device__
    void operator()( T t ) const
    {
        // I can now access f_len here (progress!)
        // But when I try to access any element via e.g., 
        // f_unchangingVector[0] I get the error below
    }
  };

: ( "thrust:: detail:: vector_base > :: operator []" ) > ( "minimum_perturbation_observer:: minPerturbFunctor:: operator() > " )

/usr/local/cuda/bin/..//include/thrust/detail/function.h(104): : ( "thrust:: device_vector > :: device_vector" ) ( "thrust:: detail:: device_function:: device_function" )

?

Answer 1

, . :

struct minPerturbFunctor
{
    state_type::value_type* m_ptr;
    size_t m_len;
    minPerturbFunctor( state_type const& x )
    : m_ptr( thrust::raw_pointer_cast(&x[0]) )
    , m_len( x.size() )
    { }

    template< class T >
    __host__ __device__
    void operator()( T t ) const
    {
        // now you can access m_ptr like m_ptr[i] 
    }
};

.