Add a constant_curve class

CMakeLists.txt

@@ -68,6 +68,7 @@ SET(${PROJECT_NAME}_HEADERS
   include/${PROJECT_NAME}/so3_linear.h
   include/${PROJECT_NAME}/se3_curve.h
   include/${PROJECT_NAME}/fwd.h
+  include/${PROJECT_NAME}/constant_curve.h
   include/${PROJECT_NAME}/helpers/effector_spline.h
   include/${PROJECT_NAME}/helpers/effector_spline_rotation.h
   include/${PROJECT_NAME}/optimization/definitions.h

include/curves/constant_curve.h

+/**
+ * \file constant_curve.h
+ * \brief class allowing to create a constant_curve curve.
+ * \author Pierre Fernbach
+ * \version 0.4
+ * \date 29/04/2020
+ */
+
+#ifndef _CLASS_CONSTANTCURVE
+#define _CLASS_CONSTANTCURVE
+
+#include "curve_abc.h"
+
+
+
+namespace curves {
+/// \class constant_curve.
+/// \brief Represents a constant_curve curve, always returning the same value and a null derivative
+///
+template <typename Time = double, typename Numeric = Time, bool Safe = false,
+          typename Point = Eigen::Matrix<Numeric, Eigen::Dynamic, 1>,
+          typename Point_derivate = Point>
+struct constant_curve : public curve_abc<Time, Numeric, Safe, Point, Point_derivate> {
+    typedef Point point_t;
+    typedef Point_derivate point_derivate_t;
+    typedef Time time_t;
+    typedef Numeric num_t;
+    typedef constant_curve<Time, Numeric, Safe, Point, Point_derivate> constant_curve_t;
+    typedef constant_curve<Time, Numeric, Safe, Point_derivate> curve_derivate_t;
+    typedef curve_abc<Time, Numeric, Safe, point_t, Point_derivate> curve_abc_t;  // parent class
+
+    /* Constructors - destructors */
+public:
+    /// \brief Empty constructor. Curve obtained this way can not perform other class functions.
+    ///
+    constant_curve() : T_min_(0), T_max_(0), dim_(0) {}
+
+    /// \brief Constructor..
+    /// \param value   : The constant value
+    /// \param T_min   : lower bound of the time interval
+    /// \param T_max   : upper bound of the time interval
+    ///
+    constant_curve(const Point& value, const time_t T_min = 0., const time_t T_max = std::numeric_limits<time_t>::max())
+        : value_(value),
+          T_min_(T_min),
+          T_max_(T_max),
+          dim_(value.size())
+    {
+        if(Safe && T_min_ > T_max_){
+            throw std::invalid_argument("can't create constant curve: min bound is higher than max bound");
+        }
+    }
+
+    /// \brief Copy constructor
+    /// \param other
+    constant_curve(const constant_curve_t& other)
+        : value_(other.value_),
+          T_min_(other.T_min_),
+          T_max_(other.T_max_),
+          dim_(other.dim_){}
+
+
+    /// \brief Destructor.
+    virtual ~constant_curve() {}
+    /* Constructors - destructors */
+
+    /*Operations*/
+    ///  \brief Evaluation of the cubic spline at time t.
+    ///  \param t : time when to evaluate the spine
+    ///  \return \f$x(t)\f$, point corresponding on curve at time t.
+    virtual point_t operator()(const time_t t) const{
+        if (Safe && (t < T_min_ || t > T_max_)) {
+          throw std::invalid_argument(
+              "error in constant curve : time t to evaluate should be in range [Tmin, Tmax] of the curve");
+        }
+        return value_;
+    }
+
+
+    ///  \brief Compute the derived curve at order N.
+    ///  Computes the derivative order N, \f$\frac{d^Nx(t)}{dt^N}\f$ of bezier curve of parametric equation x(t).
+    ///  \param order : order of derivative.
+    ///  \return \f$\frac{d^Nx(t)}{dt^N}\f$ derivative order N of the curve.
+    curve_derivate_t compute_derivate() const {
+        size_t derivate_size;
+        if(point_derivate_t::RowsAtCompileTime == Eigen::Dynamic){
+            derivate_size = dim_;
+        }else{
+            derivate_size = point_derivate_t::RowsAtCompileTime;
+        }
+        point_derivate_t value(point_derivate_t::Zero(derivate_size));
+        return curve_derivate_t(value, T_min_, T_max_);
+    }
+
+    ///  \brief Compute the derived curve at order N.
+    ///  \param order : order of derivative.
+    ///  \return A pointer to \f$\frac{d^Nx(t)}{dt^N}\f$ derivative order N of the curve.
+    virtual curve_derivate_t* compute_derivate_ptr(const std::size_t) const{
+        return new curve_derivate_t(compute_derivate());
+    }
+
+    /// \brief Evaluate the derivative of order N of curve at time t.
+    /// \param t : time when to evaluate the spline.
+    /// \param order : order of derivative.
+    /// \return \f$\frac{d^Nx(t)}{dt^N}\f$, point corresponding on derivative curve of order N at time t.
+    virtual point_derivate_t derivate(const time_t t, const std::size_t) const{
+        if (Safe && (t < T_min_ || t > T_max_)) {
+          throw std::invalid_argument(
+              "error in constant curve : time t to derivate should be in range [Tmin, Tmax] of the curve");
+        }
+        size_t derivate_size;
+        if(point_derivate_t::RowsAtCompileTime == Eigen::Dynamic){
+            derivate_size = dim_;
+        }else{
+            derivate_size = point_derivate_t::RowsAtCompileTime;
+        }
+        return point_derivate_t::Zero(derivate_size);
+    }
+
+    /**
+     * @brief isApprox check if other and *this are approximately equals given a precision treshold
+     * Only two curves of the same class can be approximately equals,
+     * for comparison between different type of curves see isEquivalent.
+     * @param other the other curve to check
+     * @param prec the precision treshold, default Eigen::NumTraits<Numeric>::dummy_precision()
+     * @return true is the two curves are approximately equals
+     */
+    virtual bool isApprox(const constant_curve_t& other,
+                          const Numeric prec = Eigen::NumTraits<Numeric>::dummy_precision()) const{
+        return curves::isApprox<num_t>(T_min_, other.min()) && curves::isApprox<num_t>(T_max_, other.max()) &&
+                dim_ == other.dim() && value_.isApprox(other.value_, prec);
+    }
+
+    virtual bool isApprox(const curve_abc_t* other,
+                          const Numeric prec = Eigen::NumTraits<Numeric>::dummy_precision()) const {
+        const constant_curve_t* other_cast = dynamic_cast<const constant_curve_t*>(other);
+        if (other_cast)
+            return isApprox(*other_cast, prec);
+        else
+            return false;
+    }
+
+    virtual bool operator==(const constant_curve_t& other) const { return isApprox(other); }
+
+    virtual bool operator!=(const constant_curve_t& other) const { return !(*this == other); }
+
+
+    /*Helpers*/
+    /// \brief Get dimension of curve.
+    /// \return dimension of curve.
+    std::size_t virtual dim() const { return dim_; }
+    /// \brief Get the minimum time for which the curve is defined
+    /// \return \f$t_{min}\f$ lower bound of time range.
+    num_t virtual min() const { return T_min_; }
+    /// \brief Get the maximum time for which the curve is defined.
+    /// \return \f$t_{max}\f$ upper bound of time range.
+    num_t virtual max() const { return T_max_; }
+    /// \brief Get the degree of the curve.
+    /// \return \f$degree\f$, the degree of the curve.
+    virtual std::size_t degree() const { return 0; }
+    /*Helpers*/
+
+    /*Attributes*/
+    Point value_;
+    time_t T_min_, T_max_;  // const
+    std::size_t dim_;       // const
+    /*Attributes*/
+
+    // Serialization of the class
+    friend class boost::serialization::access;
+
+    template <class Archive>
+    void serialize(Archive& ar, const unsigned int version) {
+      if (version) {
+        // Do something depending on version ?
+      }
+      ar& BOOST_SERIALIZATION_BASE_OBJECT_NVP(curve_abc_t);
+      ar& boost::serialization::make_nvp("value", value_);
+      ar& boost::serialization::make_nvp("T_min", T_min_);
+      ar& boost::serialization::make_nvp("T_max", T_max_);
+      ar& boost::serialization::make_nvp("dim", dim_);
+    }
+
+
+}; // struct constant_curve
+}//namespace curve
+
+#endif // _CLASS_CONSTANTCURVE

include/curves/fwd.h

@@ -21,6 +21,9 @@ struct curve_abc;
 template <typename Time, typename Numeric, bool Safe, typename Point>
 struct bezier_curve;
 
+template <typename Time, typename Numeric, bool Safe, typename Point,typename Point_derivate>
+struct constant_curve;
+
 template <typename Time, typename Numeric, bool Safe, typename Point>
 struct cubic_hermite_spline;
 
@@ -81,6 +84,7 @@ typedef boost::shared_ptr<curve_SE3_t> curve_SE3_ptr_t;
 typedef polynomial<double, double, true, pointX_t, t_pointX_t> polynomial_t;
 typedef exact_cubic<double, double, true, pointX_t, t_pointX_t, polynomial_t> exact_cubic_t;
 typedef bezier_curve<double, double, true, pointX_t> bezier_t;
+typedef constant_curve<double, double, true, pointX_t, pointX_t> constant_t;
 typedef cubic_hermite_spline<double, double, true, pointX_t> cubic_hermite_spline_t;
 typedef piecewise_curve<double, double, true, pointX_t, pointX_t, curve_abc_t> piecewise_t;
 
@@ -88,6 +92,7 @@ typedef piecewise_curve<double, double, true, pointX_t, pointX_t, curve_abc_t> p
 typedef polynomial<double, double, true, point3_t, t_point3_t> polynomial3_t;
 typedef exact_cubic<double, double, true, point3_t, t_point3_t, polynomial_t> exact_cubic3_t;
 typedef bezier_curve<double, double, true, point3_t> bezier3_t;
+typedef constant_curve<double, double, true, point3_t, point3_t> constant3_t;
 typedef cubic_hermite_spline<double, double, true, point3_t> cubic_hermite_spline3_t;
 typedef piecewise_curve<double, double, true, point3_t, point3_t, curve_3_t> piecewise3_t;
 

include/curves/serialization/curves.hpp

@@ -18,6 +18,7 @@
 #include "curves/se3_curve.h"
 #include "curves/polynomial.h"
 #include "curves/bezier_curve.h"
+#include "curves/constant_curve.h"
 #include "curves/piecewise_curve.h"
 #include "curves/exact_cubic.h"
 #include "curves/cubic_hermite_spline.h"

include/curves/serialization/registeration.hpp

@@ -35,11 +35,13 @@ void register_types(Archive& ar) {
   ar.template register_type<polynomial_t>();
   ar.template register_type<exact_cubic_t>();
   ar.template register_type<bezier_t>();
+  ar.template register_type<constant_t>();
   ar.template register_type<cubic_hermite_spline_t>();
   ar.template register_type<piecewise_t>();
   ar.template register_type<polynomial3_t>();
   ar.template register_type<exact_cubic3_t>();
   ar.template register_type<bezier3_t>();
+  ar.template register_type<constant3_t>();
   ar.template register_type<cubic_hermite_spline3_t>();
   ar.template register_type<piecewise3_t>();
   ar.template register_type<SO3Linear_t>();