casadi_de_boor.hpp

//
//    MIT No Attribution
//
//    Copyright (C) 2010-2023 Joel Andersson, Joris Gillis, Moritz Diehl, KU Leuven.
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// SYMBOL "de_boor"
template<typename T1>
void casadi_de_boor(T1 x, const T1* knots, casadi_int n_knots, casadi_int degree, T1* boor) {
  // length boor: n_knots-1
  casadi_int d, i;
  for (d=1;d<degree+1;++d) {
    for (i=0;i<n_knots-d-1;++i) {
      T1 b, bottom;
      b = 0;
      bottom = knots[i + d] - knots[i];
      if (bottom) b = (x - knots[i]) * boor[i] / bottom;
      bottom = knots[i + d + 1] - knots[i + 1];
      if (bottom) b += (knots[i + d + 1] - x) * boor[i + 1] / bottom;
      boor[i] = b;
    }
  }
}