nodes.cc

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#include <towr/variables/nodes.h>


namespace towr {


Nodes::Nodes (int n_dim, const std::string& name)
    : VariableSet(kSpecifyLater, name)
{
  n_dim_ = n_dim;
}

void
Nodes::InitMembers(int n_nodes, int n_variables)
{
  nodes_  = std::vector<Node>(n_nodes, Node(n_dim_));
  bounds_ = VecBound(n_variables, ifopt::NoBound);
  SetRows(n_variables);
}

void
Nodes::InitializeNodesTowardsGoal(const VectorXd& initial_pos,
                               const VectorXd& final_pos,
                               double t_total)
{
  VectorXd dp = final_pos-initial_pos;
  VectorXd average_velocity = dp/t_total;
  int num_nodes = nodes_.size();
  for (int i=0; i<nodes_.size(); ++i) {
    Node n(n_dim_);
    n.at(kPos) = initial_pos + i/static_cast<double>(num_nodes-1)*dp;
    n.at(kVel) = average_velocity;
    nodes_.at(i) = n;
  }
}

Nodes::IndexInfo::IndexInfo(int node_id, Dx deriv, int node_dim)
{
  node_id_    = node_id;
  node_deriv_ = deriv;
  node_dim_   = node_dim;
}

int
Nodes::Index(int node_id, Dx deriv, int node_dim) const
{
  return Index(IndexInfo(node_id, deriv, node_dim));
}

int
Nodes::Index(const IndexInfo& n) const
{
  // could also cache this as map for more efficiency, but adding complexity
  for (int idx=0; idx<GetRows(); ++idx)
    for ( IndexInfo node_info : GetNodeInfoAtOptIndex(idx))
      if ( node_info == n )
        return idx;

  assert(false); // index representing these quantities doesn't exist
}

// reverse of the above
std::vector<Nodes::IndexInfo>
Nodes::GetNodeInfoAtOptIndex (int idx) const
{
  std::vector<IndexInfo> nodes;

  // always two consecutive node pairs are equal
  int n_opt_values_per_node_ = 2*n_dim_;
  int internal_id = idx%n_opt_values_per_node_; // 0...6 (p.x, p.y, p.z, v.x, v.y. v.z)

  IndexInfo node;
  node.node_deriv_ = internal_id<n_dim_? kPos : kVel;
  node.node_dim_   = internal_id%n_dim_;
  node.node_id_    = std::floor(idx/n_opt_values_per_node_);

  nodes.push_back(node);

  return nodes;
}

Eigen::VectorXd
Nodes::GetValues () const
{
  VectorXd x(GetRows());

  for (int idx=0; idx<x.rows(); ++idx)
    for (auto info : GetNodeInfoAtOptIndex(idx))
      x(idx) = nodes_.at(info.node_id_).at(info.node_deriv_)(info.node_dim_);

  return x;
}

void
Nodes::SetVariables (const VectorXd& x)
{
  for (int idx=0; idx<x.rows(); ++idx)
    for (auto info : GetNodeInfoAtOptIndex(idx))
      nodes_.at(info.node_id_).at(info.node_deriv_)(info.node_dim_) = x(idx);

  UpdateObservers();
}

void
Nodes::UpdateObservers() const
{
  for (auto& o : observers_)
    o->UpdateNodes();
}

void
Nodes::AddObserver(ObserverPtr const o)
{
   observers_.push_back(o);
}

int
Nodes::GetNodeId (int poly_id, Side side)
{
  return poly_id + side;
}

const std::vector<Node>
Nodes::GetBoundaryNodes(int poly_id) const
{
  std::vector<Node> nodes;
  nodes.push_back(nodes_.at(GetNodeId(poly_id, Side::Start)));
  nodes.push_back(nodes_.at(GetNodeId(poly_id, Side::End)));
  return nodes;
}

int
Nodes::GetDim() const
{
  return n_dim_;
}

int
Nodes::GetPolynomialCount() const
{
  return nodes_.size() - 1;
}

Nodes::VecBound
Nodes::GetBounds () const
{
  return bounds_;
}

const std::vector<Node>
Nodes::GetNodes() const
{
  return nodes_;
}

void
Nodes::AddBounds(int node_id, Dx deriv,
                         const std::vector<int>& dimensions,
                         const VectorXd& val)
{
  for (auto dim : dimensions)
    AddBound(IndexInfo(node_id, deriv, dim), val(dim));
}

void
Nodes::AddBound (const IndexInfo& node_info, double val)
{
  for (int idx=0; idx<GetRows(); ++idx)
    for (auto info : GetNodeInfoAtOptIndex(idx))
      if (info == node_info)
        bounds_.at(idx) = ifopt::Bounds(val, val);
}

void
Nodes::AddStartBound (Dx d,
                           const std::vector<int>& dimensions,
                           const VectorXd& val)
{
  AddBounds(0, d, dimensions, val);
}

void
Nodes::AddFinalBound (Dx deriv,
                           const std::vector<int>& dimensions,
                           const VectorXd& val)
{
  AddBounds(nodes_.size()-1, deriv, dimensions, val);
}

int
Nodes::IndexInfo::operator==(const IndexInfo& right) const
{
  return (node_id_    == right.node_id_)
      && (node_deriv_ == right.node_deriv_)
      && (node_dim_   == right.node_dim_);
};

} /* namespace towr */