PolynomialBivariate.cpp

 
/* SPDX-License-Identifier: CC0-1.0 */
#include <iostream>
#include "PolynomialBivariate.h"
 
namespace Isis {
  PolynomialBivariate::PolynomialBivariate(int degree) :
    Isis::BasisFunction("PolynomialBivariate", 2, ((degree + 1) * (degree + 2)) / 2) {
    p_degree = degree;
  }
 
  void PolynomialBivariate::Expand(const std::vector<double> &vars) {
    std::vector<std::vector<double> > terms;
    terms.resize(p_degree + 1);
    terms[0].push_back(1.0);
    for(int i = 1; i <= p_degree; i++) {
      for(int t = 0; t < (int)terms[i-1].size(); t++) {
        terms[i].push_back(terms[i-1][t] * vars[0]);
        if(t == ((int)terms[i-1].size() - 1)) {
          terms[i].push_back(terms[i-1][t] * vars[1]);
        }
      }
    }
 
    p_terms.clear();
    for(int i = 0; i <= p_degree; i++) {
      for(int t = 0; t < (int)terms[i].size(); t++) {
        p_terms.push_back(terms[i][t]);
      }
    }
  }
} // end namespace isis