source/interpolate/linearspline.h

   1 #ifndef MSP_INTERPOLATE_LINEARSPLINE_H_
   2 #define MSP_INTERPOLATE_LINEARSPLINE_H_
   3
   4 #include <vector>
   5 #include "spline.h"
   6
   7 namespace Msp {
   8 namespace Interpolate {
   9
  10 /**
  11 A very simple type of spline.  It interpolates the value linearly between
  12 knots.
  13 */
  14 template<typename T, unsigned N = 1>
  15 class LinearSpline: public Spline<T, 1, N>
  16 {
  17 public:
  18         using typename Spline<T, 1, N>::Value;
  19         using typename Spline<T, 1, N>::Knot;
  20
  21         LinearSpline(const std::vector<Knot> &k):
  22                 Spline<T, 1, N>(k.front())
  23         {
  24                 typedef SplineValue<T, N> SV;
  25
  26                 this->reserve(k.size()-1);
  27                 for(unsigned i=1; i<k.size(); ++i)
  28                 {
  29                         T dx = k[i].x-k[i-1].x;
  30                         Value slope = (k[i].y-k[i-1].y)/dx;
  31                         Polynomial<T, 1> p[N];
  32                         for(unsigned j=0; j<N; ++j)
  33                                 p[j] = Polynomial<T, 1>(LinAl::Vector<T, 2>(SV::get(slope, j), SV::get(k[i-1].y, j)-k[i-1].x*SV::get(slope, j)));
  34                         this->add_segment(p, k[i].x);
  35                 }
  36         }
  37 };
  38
  39 } // namespace Interpolate
  40 } // namespace Msp
  41
  42 #endif