/usr/include/deal.II/base/function_cspline.h is in libdeal.ii-dev 8.5.1-3.
This file is owned by root:root, with mode 0o644.
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//
// Copyright (C) 2016 - 2017 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------
#ifndef dealii__function_cspline_h
#define dealii__function_cspline_h
#include <deal.II/base/config.h>
#ifdef DEAL_II_WITH_GSL
#include <deal.II/base/function.h>
#include <deal.II/base/point.h>
#include <deal.II/base/thread_management.h>
#include <gsl/gsl_spline.h>
DEAL_II_NAMESPACE_OPEN
namespace Functions
{
DeclException1 (ExcCSplineEmpty,
int,
<< "Interpolation points vector size can not be <"<<arg1<<">."
);
DeclException2 (ExcCSplineSizeMismatch,
int,
int,
<< "The size of interpolation points <"<<arg1<<"> is different from the size of interpolation values <" << arg2 <<">."
);
DeclException3 (ExcCSplineOrder,
int,
double,
double,
<< "The input interpolation points are not strictly ordered : " << std::endl << "x[" << arg1 << "] = "<< arg2 <<" >= x["<<(arg1+1)<<"] = "<<arg3 <<"."
);
DeclException3 (ExcCSplineRange,
double,
double,
double,
<< "Spline function can not be evaluated outside of the interpolation range: "<< std::endl << arg1 << " is not in ["<< arg2<<";"<<arg3<<"]."
);
/**
* The cubic spline function using GNU Scientific Library.
* The resulting curve is piecewise cubic on each interval, with matching first
* and second derivatives at the supplied data-points. The second derivative
* is chosen to be zero at the first point and last point.
*
* @note This function is only implemented for dim==1 .
*
* @author Denis Davydov
* @date 2016
*/
template <int dim>
class CSpline : public Function<dim>
{
public:
/**
* Constructor which should be provided with a set of points at which
* interpolation is to be done @p interpolation_points and a set of function
* values @p interpolation_values .
*/
CSpline(const std::vector<double> &interpolation_points,
const std::vector<double> &interpolation_values);
/**
* Virtual destructor.
*/
virtual ~CSpline();
virtual double value (const Point<dim> &point,
const unsigned int component = 0) const;
virtual Tensor<1,dim> gradient (const Point<dim> &p,
const unsigned int component = 0) const;
virtual SymmetricTensor<2,dim> hessian (const Point<dim> &p,
const unsigned int component = 0) const;
virtual double laplacian(const Point< dim > &p,
const unsigned int component = 0) const;
std::size_t memory_consumption () const;
private:
/**
* Points at which interpolation is provided
*/
const std::vector<double> interpolation_points;
/**
* Values of the function at interpolation points
*/
const std::vector<double> interpolation_values;
/**
* GSL accelerator for spline interpolation
*/
gsl_interp_accel *acc;
/**
* GSL cubic spline interpolator
*/
gsl_spline *cspline;
/**
* A mutex for accelerator object.
*/
mutable Threads::Mutex acc_mutex;
};
}
DEAL_II_NAMESPACE_CLOSE
#endif
#endif
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