CircularMapper1d.h

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#ifndef NPSTAT_CIRCULARMAPPER1D_HH_
#define NPSTAT_CIRCULARMAPPER1D_HH_

#include <cmath>

#include "JetMETCorrections/InterpolationTables/interface/LinearMapper1d.h"

namespace npstat {
  class CircularMapper1d {
  public:
    inline CircularMapper1d() : a_(1.0), b_(0.0), period_(2.0 * M_PI) {}

    inline CircularMapper1d(const double ca, const double cb, const double cperiod)
        : a_(ca), b_(cb), period_(std::abs(cperiod)) {
      check();
    }

    inline CircularMapper1d(const LinearMapper1d& mapper, const double cperiod)
        : a_(mapper.a()), b_(mapper.b()), period_(std::abs(cperiod)) {
      check();
    }

    inline double operator()(const double& x) const {
      double value = a_ * x + b_;
      value -= period_ * floor(value / period_);
      if (value > period_ / 2.0)
        value -= period_;
      return value;
    }

    inline double a() const { return a_; }
    inline double b() const { return b_; }
    inline double period() const { return period_; }
    inline LinearMapper1d linearMapper() const { return LinearMapper1d(a_, b_); }

  private:
    inline void check() {
      if (!period_)
        throw npstat::NpstatInvalidArgument(
            "In npstat::CircularMapper1d constructor: "
            "invalid period argument (can not be 0)");
    }

    double a_;
    double b_;
    double period_;
  };
}  // namespace npstat

#endif  // NPSTAT_CIRCULARMAPPER1D_HH_