84 lines
2.0 KiB
C++
84 lines
2.0 KiB
C++
/* ----------------------------------------------------------------------------
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* GTSAM Copyright 2010, Georgia Tech Research Corporation,
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* Atlanta, Georgia 30332-0415
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* All Rights Reserved
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* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
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* See LICENSE for the license information
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* -------------------------------------------------------------------------- */
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/**
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* @file Cyclic.h
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* @brief Cyclic group, i.e., the integers modulo N
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* @author Frank Dellaert
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**/
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#include <gtsam/base/Group.h>
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#include <cstddef>
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#include <string>
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#include <iostream>
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#include <assert.h>
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namespace gtsam {
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/// Cyclic group of order N
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template<size_t N>
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class Cyclic {
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size_t i_; ///< we just use an unsigned int
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public:
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/// Constructor
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Cyclic(size_t i) :
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i_(i) {
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assert(i < N);
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}
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/// Idenity element
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static Cyclic Identity() {
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return Cyclic(0);
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}
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/// Cast to size_t
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operator size_t() const {
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return i_;
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}
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/// Addition modulo N
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Cyclic operator+(const Cyclic& h) const {
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return (i_ + h.i_) % N;
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}
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/// Subtraction modulo N
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Cyclic operator-(const Cyclic& h) const {
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return (N + i_ - h.i_) % N;
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}
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/// Inverse
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Cyclic operator-() const {
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return (N - i_) % N;
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}
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/// print with optional string
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void print(const std::string& s = "") const {
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std::cout << s << i_ << std::endl;
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}
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/// equals with an tolerance, prints out message if unequal
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bool equals(const Cyclic& other, double tol = 1e-9) const {
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return other.i_ == i_;
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}
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};
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/// Define cyclic group traits to be a model of the Group concept
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template<size_t N>
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struct traits<Cyclic<N> > {
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typedef group_tag structure_category;GTSAM_ADDITIVE_GROUP(Cyclic<N>)
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static Cyclic<N> Identity() {
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return Cyclic<N>::Identity();
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}
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static bool Equals(const Cyclic<N>& a, const Cyclic<N>& b,
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double tol = 1e-9) {
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return a.equals(b, tol);
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}
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static void Print(const Cyclic<N>& c, const std::string &s = "") {
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c.print(s);
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}
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};
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} // \namespace gtsam
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