node_spline.cc

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#include <towr/variables/node_spline.h>

#include <towr/variables/nodes.h>

namespace towr {

NodeSpline::NodeSpline(NodeSubjectPtr const node_variables,
                       const VecTimes& polynomial_durations)
    :   Spline(polynomial_durations, node_variables->GetDim()),
        NodesObserver(node_variables)
{
  UpdateNodes();
  jac_wrt_nodes_structure_ = Jacobian(node_variables->GetDim(), node_variables->GetRows());
}


void
NodeSpline::UpdateNodes ()
{
  for (int i=0; i<cubic_polys_.size(); ++i) {
    auto nodes = node_values_->GetBoundaryNodes(i);
    cubic_polys_.at(i).SetNodes(nodes.front(), nodes.back());
  }

  UpdatePolynomialCoeff();
}

int
NodeSpline::GetNodeVariablesCount() const
{
  return node_values_->GetRows();
}

NodeSpline::Jacobian
NodeSpline::GetJacobianWrtNodes (double t_global, Dx dxdt) const
{
  int id; double t_local;
  std::tie(id, t_local) = GetLocalTime(t_global, GetPolyDurations());

  return GetJacobianWrtNodes(id, t_local, dxdt);
}

NodeSpline::Jacobian
NodeSpline::GetJacobianWrtNodes (int id, double t_local, Dx dxdt) const
{
  Jacobian jac = jac_wrt_nodes_structure_;
  FillJacobianWrtNodes(id, t_local, dxdt, jac, false);

  // needed to avoid Eigen::assert failure "wrong storage order" triggered
  // in dynamic_constraint.cc
  jac.makeCompressed();

  return jac;
}

void
NodeSpline::FillJacobianWrtNodes (int poly_id, double t_local, Dx dxdt,
                                  Jacobian& jac, bool fill_with_zeros) const
{
  for (int idx=0; idx<jac.cols(); ++idx) {
    for (auto info : node_values_->GetNodeInfoAtOptIndex(idx)) {
      for (auto side : {Nodes::Side::Start, Nodes::Side::End}) { // every jacobian is affected by two nodes

        int node = node_values_->GetNodeId(poly_id, side);

        if (node == info.node_id_) {
          double val = 0.0;

          if (side == Nodes::Side::Start)
            val = cubic_polys_.at(poly_id).GetDerivativeWrtStartNode(dxdt, info.node_deriv_, t_local);
          else if (side == Nodes::Side::End)
            val = cubic_polys_.at(poly_id).GetDerivativeWrtEndNode(dxdt, info.node_deriv_, t_local);
          else
            assert(false); // this shouldn't happen

          // if only want structure
          if (fill_with_zeros)
            val = 0.0;

          jac.coeffRef(info.node_dim_, idx) += val;
        }
      }
    }
  }
}

} /* namespace towr */