Spline.h

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#ifndef SimTK_SIMMATH_SPLINE_H_
#define SimTK_SIMMATH_SPLINE_H_

/* -------------------------------------------------------------------------- *
 *                      SimTK Core: SimTK Simmath(tm)                         *
 * -------------------------------------------------------------------------- *
 * This is part of the SimTK Core biosimulation toolkit originating from      *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org.               *
 *                                                                            *
 * Portions copyright (c) 2008-2009 Stanford University and the Authors.      *
 * Authors: Peter Eastman                                                     *
 * Contributors:                                                              *
 *                                                                            *
 * Permission is hereby granted, free of charge, to any person obtaining a    *
 * copy of this software and associated documentation files (the "Software"), *
 * to deal in the Software without restriction, including without limitation  *
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,   *
 * and/or sell copies of the Software, and to permit persons to whom the      *
 * Software is furnished to do so, subject to the following conditions:       *
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 * The above copyright notice and this permission notice shall be included in *
 * all copies or substantial portions of the Software.                        *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,   *
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL    *
 * THE AUTHORS, CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,    *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR      *
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 * -------------------------------------------------------------------------- */

#include "SimTKcommon.h"
#include "simmath/internal/common.h"
#include "simmath/internal/GCVSPLUtil.h"

#include <limits>

namespace SimTK {

template <class T>
class Spline_ : public Function_<T> {
public:
    Spline_(int degree, const Vector& x, const Vector_<T>& y) : impl(new SplineImpl(degree, x, y)) {
    }
    Spline_(const Spline_& copy) : impl(copy.impl) {
        impl->referenceCount++;
    }
    Spline_() : impl(NULL) {
    }
    Spline_& operator=(const Spline_& copy) {
        if (impl) {
            impl->referenceCount--;
            if (impl->referenceCount == 0)
                delete impl;
        }
        impl = copy.impl;
        assert(impl);
        impl->referenceCount++;
        return *this;
    }
    ~Spline_() {
        if (impl) {
            impl->referenceCount--;
            if (impl->referenceCount == 0)
                delete impl;
        }
    }
    T calcValue(const Vector& x) const {
        assert(impl);
        assert(x.size() == 1);
        return impl->getValue(x[0]);
    }
    T calcDerivative(const Array_<int>& derivComponents, const Vector& x) const {
        assert(impl);
        assert(x.size() == 1);
        assert(derivComponents.size() > 0);
        return impl->getDerivative(derivComponents.size(), x[0]);
    }
    int getArgumentSize() const {
        return 1;
    }
    int getMaxDerivativeOrder() const {
        return std::numeric_limits<int>::max();
    }
    const Vector& getControlPointLocations() const {
        assert(impl);
        return impl->x;
    }
    const Vector_<T>& getControlPointValues() const {
        assert(impl);
        return impl->y;
    }
    int getSplineDegree() const {
        assert(impl);
        return impl->degree;
    }

    T calcDerivative(const std::vector<int>& derivComponents, const Vector& x) const 
    {   return calcDerivative(ArrayViewConst_<int>(derivComponents),x); }
private:
    class SplineImpl;
    SplineImpl* impl;
};

typedef Spline_<Real> Spline;

template <class T>
class Spline_<T>::SplineImpl {
public:
    SplineImpl(int degree, const Vector& x, const Vector_<T>& y) : referenceCount(1), degree(degree), x(x), y(y) {
    }
    ~SplineImpl() {
        assert(referenceCount == 0);
    }
    T getValue(Real t) const {
        return GCVSPLUtil::splder(0, degree, t, x, y);
    }
    T getDerivative(int derivOrder, Real t) const {
        return GCVSPLUtil::splder(derivOrder, degree, t, x, y);
    }
    int referenceCount;
    int degree;
    Vector x;
    Vector_<T> y;
};

} // namespace SimTK

#endif // SimTK_SIMMATH_SPLINE_H_