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opm-common/opm/material/common/UniformTabulated2DFunction.hpp
2021-06-18 13:24:02 +02:00

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
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 2 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/>.
Consult the COPYING file in the top-level source directory of this
module for the precise wording of the license and the list of
copyright holders.
*/
/*!
* \file
*
* \copydoc Opm::UniformTabulated2DFunction
*/
#ifndef OPM_UNIFORM_TABULATED_2D_FUNCTION_HPP
#define OPM_UNIFORM_TABULATED_2D_FUNCTION_HPP
#include <opm/material/common/Exceptions.hpp>
#include <opm/material/common/MathToolbox.hpp>
#include <vector>
#include <assert.h>
namespace Opm {
/*!
* \brief Implements a scalar function that depends on two variables and which is sampled
* on an uniform X-Y grid.
*
* This class can be used when the sampling points are calculated at
* run time.
*/
template <class Scalar>
class UniformTabulated2DFunction
{
public:
UniformTabulated2DFunction()
{ }
/*!
* \brief Constructor where the tabulation parameters are already
* provided.
*/
UniformTabulated2DFunction(Scalar minX, Scalar maxX, unsigned m,
Scalar minY, Scalar maxY, unsigned n)
{
resize(minX, maxX, m, minY, maxY, n);
}
UniformTabulated2DFunction(Scalar minX, Scalar maxX, unsigned m,
Scalar minY, Scalar maxY, unsigned n,
const std::vector<std::vector<Scalar>>& vals)
{
resize(minX, maxX, m, minY, maxY, n);
for (unsigned i = 0; i < m; ++i)
for (unsigned j = 0; j < n; ++j)
this->setSamplePoint(i, j, vals[i][j]);
}
/*!
* \brief Resize the tabulation to a new range.
*/
void resize(Scalar minX, Scalar maxX, unsigned m,
Scalar minY, Scalar maxY, unsigned n)
{
samples_.resize(m*n);
m_ = m;
n_ = n;
xMin_ = minX;
xMax_ = maxX;
yMin_ = minY;
yMax_ = maxY;
}
/*!
* \brief Returns the minimum of the X coordinate of the sampling points.
*/
Scalar xMin() const
{ return xMin_; }
/*!
* \brief Returns the maximum of the X coordinate of the sampling points.
*/
Scalar xMax() const
{ return xMax_; }
/*!
* \brief Returns the minimum of the Y coordinate of the sampling points.
*/
Scalar yMin() const
{ return yMin_; }
/*!
* \brief Returns the maximum of the Y coordinate of the sampling points.
*/
Scalar yMax() const
{ return yMax_; }
/*!
* \brief Returns the number of sampling points in X direction.
*/
unsigned numX() const
{ return m_; }
/*!
* \brief Returns the number of sampling points in Y direction.
*/
unsigned numY() const
{ return n_; }
/*!
* \brief Return the position on the x-axis of the i-th interval.
*/
Scalar iToX(unsigned i) const
{
assert(i < numX());
return xMin() + i*(xMax() - xMin())/(numX() - 1);
}
/*!
* \brief Return the position on the y-axis of the j-th interval.
*/
Scalar jToY(unsigned j) const
{
assert(j < numY());
return yMin() + j*(yMax() - yMin())/(numY() - 1);
}
/*!
* \brief Return the interval index of a given position on the x-axis.
*
* This method returns a *floating point* number. The integer part
* should be interpreted as interval, the decimal places are the
* position of the x value between the i-th and the (i+1)-th
* sample point.
*/
template <class Evaluation>
Evaluation xToI(const Evaluation& x) const
{ return (x - xMin())/(xMax() - xMin())*(numX() - 1); }
/*!
* \brief Return the interval index of a given position on the y-axis.
*
* This method returns a *floating point* number. The integer part
* should be interpreted as interval, the decimal places are the
* position of the y value between the j-th and the (j+1)-th
* sample point.
*/
template <class Evaluation>
Evaluation yToJ(const Evaluation& y) const
{ return (y - yMin())/(yMax() - yMin())*(numY() - 1); }
/*!
* \brief Returns true iff a coordinate lies in the tabulated range
*/
template <class Evaluation>
bool applies(const Evaluation& x, const Evaluation& y) const
{
return
xMin() <= x && x <= xMax() &&
yMin() <= y && y <= yMax();
}
/*!
* \brief Evaluate the function at a given (x,y) position.
*
* If this method is called for a value outside of the tabulated
* range, a \c Opm::NumericalIssue exception is thrown.
*/
template <class Evaluation>
Evaluation eval(const Evaluation& x, const Evaluation& y) const
{
#ifndef NDEBUG
if (!applies(x,y))
{
throw NumericalIssue("Attempt to get tabulated value for ("
+std::to_string(double(scalarValue(x)))+", "+std::to_string(double(scalarValue(y)))
+") on a table of extend "
+std::to_string(xMin())+" to "+std::to_string(xMax())+" times "
+std::to_string(yMin())+" to "+std::to_string(yMax()));
};
#endif
Evaluation alpha = xToI(x);
Evaluation beta = yToJ(y);
unsigned i =
static_cast<unsigned>(
std::max(0, std::min(static_cast<int>(numX()) - 2,
static_cast<int>(scalarValue(alpha)))));
unsigned j =
static_cast<unsigned>(
std::max(0, std::min(static_cast<int>(numY()) - 2,
static_cast<int>(scalarValue(beta)))));
alpha -= i;
beta -= j;
// bi-linear interpolation
const Evaluation& s1 = getSamplePoint(i, j)*(1.0 - alpha) + getSamplePoint(i + 1, j)*alpha;
const Evaluation& s2 = getSamplePoint(i, j + 1)*(1.0 - alpha) + getSamplePoint(i + 1, j + 1)*alpha;
return s1*(1.0 - beta) + s2*beta;
}
/*!
* \brief Get the value of the sample point which is at the
* intersection of the \f$i\f$-th interval of the x-Axis
* and the \f$j\f$-th of the y-Axis.
*/
Scalar getSamplePoint(unsigned i, unsigned j) const
{
assert(i < m_);
assert(j < n_);
return samples_[j*m_ + i];
}
/*!
* \brief Set the value of the sample point which is at the
* intersection of the \f$i\f$-th interval of the x-Axis
* and the \f$j\f$-th of the y-Axis.
*/
void setSamplePoint(unsigned i, unsigned j, Scalar value)
{
assert(i < m_);
assert(j < n_);
samples_[j*m_ + i] = value;
}
bool operator==(const UniformTabulated2DFunction<Scalar>& data) const
{
return samples_ == data.samples_ &&
m_ == data.m_ &&
n_ == data.n_ &&
xMin_ == data.xMin_ &&
xMax_ == data.xMax_ &&
yMin_ == data.yMin_ &&
yMax_ == data.yMax_;
}
private:
// the vector which contains the values of the sample points
// f(x_i, y_j). don't use this directly, use getSamplePoint(i,j)
// instead!
std::vector<Scalar> samples_;
// the number of sample points in x direction
unsigned m_;
// the number of sample points in y direction
unsigned n_;
// the range of the tabulation on the x axis
Scalar xMin_;
Scalar xMax_;
// the range of the tabulation on the y axis
Scalar yMin_;
Scalar yMax_;
};
} // namespace Opm
#endif