spline.cc

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#include <towr/variables/spline.h>

#include <numeric> // std::accumulate

namespace towr {

Spline::Spline(const VecTimes& poly_durations, int n_dim)
{
  uint n_polys = poly_durations.size();

  cubic_polys_.assign(n_polys, CubicHermitePolynomial(n_dim));
  for (int i=0; i<cubic_polys_.size(); ++i) {
    cubic_polys_.at(i).SetDuration(poly_durations.at(i));
  }

  UpdatePolynomialCoeff();
}

int
Spline::GetSegmentID(double t_global, const VecTimes& durations)
{
  double eps = 1e-10; // double precision
  assert(t_global >= 0.0);

   double t = 0;
   int i=0;
   for (double d: durations) {
     t += d;

     if (t >= t_global-eps) // at junctions, returns previous spline (=)
       return i;

     i++;
   }

   assert(false); // this should never be reached
}

std::pair<int,double>
Spline::GetLocalTime (double t_global, const VecTimes& durations) const
{
  int id = GetSegmentID(t_global, durations);

  double t_local = t_global;
  for (int i=0; i<id; i++)
    t_local -= durations.at(i);

  return std::make_pair(id, t_local);
}

const State
Spline::GetPoint(double t_global) const
{
  int id; double t_local;
  std::tie(id, t_local) = GetLocalTime(t_global, GetPolyDurations());

  return GetPoint(id, t_local);
}

const State
Spline::GetPoint(int poly_id, double t_local) const
{
  return cubic_polys_.at(poly_id).GetPoint(t_local);
}

void
Spline::UpdatePolynomialCoeff()
{
  for (auto& p : cubic_polys_)
    p.UpdateCoeff();
}

int
Spline::GetPolynomialCount () const
{
  return cubic_polys_.size();
}

Spline::VecTimes
Spline::GetPolyDurations() const
{
  VecTimes poly_durations;
  for (const auto& p : cubic_polys_)
    poly_durations.push_back(p.GetDuration());

  return poly_durations;
}

double
Spline::GetTotalTime() const
{
  auto v = GetPolyDurations();
  return std::accumulate(v.begin(), v.end(), 0.0);
}

} /* namespace towr */