opm-core/opm/core/utility/UniformTableLinear.hpp
2015-10-08 11:42:15 +02:00

269 lines
7.9 KiB
C++

/*
Copyright 2010 SINTEF ICT, Applied Mathematics.
This file is part of the Open Porous Media project (OPM).
OPM is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OPM is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with OPM. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef OPM_UNIFORMTABLELINEAR_HEADER_INCLUDED
#define OPM_UNIFORMTABLELINEAR_HEADER_INCLUDED
#include <cmath>
#include <exception>
#include <vector>
#include <utility>
#include <iostream>
#include <opm/common/ErrorMacros.hpp>
namespace Opm {
/// @brief This class uses linear interpolation to compute the value
/// (and its derivative) of a function f sampled at uniform points.
/// @tparam T the range type of the function (should be an algebraic ring type)
template<typename T>
class UniformTableLinear
{
public:
/// @brief Default constructor.
UniformTableLinear();
/// @brief Construct from vector of y-values.
/// @param xmin the x value corresponding to the first y value.
/// @param xmax the x value corresponding to the last y value.
/// @param y_values vector of range values.
UniformTableLinear(double xmin,
double xmax,
const std::vector<T>& y_values);
/// @brief Construct from array of y-values.
/// @param xmin the x value corresponding to the first y value.
/// @param xmax the x value corresponding to the last y value.
/// @param y_values array of range values.
/// @param num_y_values the number of values in y_values.
UniformTableLinear(double xmin,
double xmax,
const T* y_values,
int num_y_values);
/// @brief Get the domain.
/// @return the domain as a pair of doubles.
std::pair<double, double> domain();
/// @brief Rescale the domain.
/// @param new_domain the new domain as a pair of doubles.
void rescaleDomain(std::pair<double, double> new_domain);
/// @brief Evaluate the value at x.
/// @param x a domain value
/// @return f(x)
double operator()(const double x) const;
/// @brief Evaluate the derivative at x.
/// @param x a domain value
/// @return f'(x)
double derivative(const double x) const;
/// @brief Equality operator.
/// @param other another UniformTableLinear.
/// @return true if they are represented exactly alike.
bool operator==(const UniformTableLinear& other) const;
/// @brief Policies for how to behave when trying to evaluate outside the domain.
enum RangePolicy {Throw = 0, ClosestValue = 1, Extrapolate = 2};
/// @brief Sets the behavioural policy for evaluation to the left of the domain.
/// @param rp the policy
void setLeftPolicy(RangePolicy rp);
/// @brief Sets the behavioural policy for evaluation to the right of the domain.
/// @param rp the policy
void setRightPolicy(RangePolicy rp);
protected:
double xmin_;
double xmax_;
double xdelta_;
std::vector<T> y_values_;
RangePolicy left_;
RangePolicy right_;
template <typename U>
friend std::ostream& operator<<(std::ostream& os, const UniformTableLinear<U>& t);
};
// Member implementations.
template<typename T>
inline
UniformTableLinear<T>
::UniformTableLinear()
: left_(ClosestValue), right_(ClosestValue)
{
}
template<typename T>
inline
UniformTableLinear<T>
::UniformTableLinear(double xmin,
double xmax,
const std::vector<T>& y_values)
: xmin_(xmin), xmax_(xmax), y_values_(y_values),
left_(ClosestValue), right_(ClosestValue)
{
assert(xmax > xmin);
assert(y_values.size() > 1);
xdelta_ = (xmax - xmin)/(y_values.size() - 1);
}
template<typename T>
inline
UniformTableLinear<T>
::UniformTableLinear(double xmin,
double xmax,
const T* y_values,
int num_y_values)
: xmin_(xmin), xmax_(xmax),
y_values_(y_values, y_values + num_y_values),
left_(ClosestValue), right_(ClosestValue)
{
assert(xmax > xmin);
assert(y_values_.size() > 1);
xdelta_ = (xmax - xmin)/(y_values_.size() - 1);
}
template<typename T>
inline std::pair<double, double>
UniformTableLinear<T>
::domain()
{
return std::make_pair(xmin_, xmax_);
}
template<typename T>
inline void
UniformTableLinear<T>
::rescaleDomain(std::pair<double, double> new_domain)
{
xmin_ = new_domain.first;
xmax_ = new_domain.second;
xdelta_ = (xmax_ - xmin_)/(y_values_.size() - 1);
}
template<typename T>
inline double
UniformTableLinear<T>
::operator()(const double xparam) const
{
// Implements ClosestValue policy.
double x = std::min(xparam, xmax_);
x = std::max(x, xmin_);
// Lookup is easy since we are uniform in x.
double pos = (x - xmin_)/xdelta_;
double posi = std::floor(pos);
int left = int(posi);
if (left == int(y_values_.size()) - 1) {
// We are at xmax_
return y_values_.back();
}
double w = pos - posi;
return (1.0 - w)*y_values_[left] + w*y_values_[left + 1];
}
template<typename T>
inline double
UniformTableLinear<T>
::derivative(const double xparam) const
{
// Implements derivative consistent
// with ClosestValue policy for function
double value;
if (xparam > xmax_ || xparam < xmin_) {
value = 0.0;
} else {
double x = std::min(xparam, xmax_);
x = std::max(x, xmin_);
// Lookup is easy since we are uniform in x.
double pos = (x - xmin_)/xdelta_;
double posi = std::floor(pos);
int left = int(posi);
if (left == int(y_values_.size()) - 1) {
// We are at xmax_
--left;
}
value = (y_values_[left + 1] - y_values_[left])/xdelta_;
}
return value;
}
template<typename T>
inline bool
UniformTableLinear<T>
::operator==(const UniformTableLinear<T>& other) const
{
return xmin_ == other.xmin_
&& xdelta_ == other.xdelta_
&& y_values_ == other.y_values_
&& left_ == other.left_
&& right_ == other.right_;
}
template<typename T>
inline void
UniformTableLinear<T>
::setLeftPolicy(RangePolicy rp)
{
if (rp != ClosestValue) {
OPM_THROW(std::runtime_error, "Only ClosestValue RangePolicy implemented.");
}
left_ = rp;
}
template<typename T>
inline void
UniformTableLinear<T>
::setRightPolicy(RangePolicy rp)
{
if (rp != ClosestValue) {
OPM_THROW(std::runtime_error, "Only ClosestValue RangePolicy implemented.");
}
right_ = rp;
}
template <typename T>
inline std::ostream& operator<<(std::ostream& os, const UniformTableLinear<T>& t)
{
int n = t.y_values_.size();
for (int i = 0; i < n; ++i) {
double f = double(i)/double(n - 1);
os << (1.0 - f)*t.xmin_ + f*t.xmax_
<< " " << t.y_values_[i] << '\n';
}
return os;
}
namespace utils
{
using Opm::UniformTableLinear;
}
} // namespace Opm
#endif // OPM_UNIFORMTABLELINEAR_HEADER_INCLUDED