55 lines
2.0 KiB
C++
55 lines
2.0 KiB
C++
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// Copyright Nick Thompson, 2021
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// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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// This implements bilinear interpolation on a uniform grid.
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// If dx and dy are both positive, then the (x,y) = (x0, y0) is associated with data index 0 (herein referred to as f[0])
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// The point (x0 + dx, y0) is associated with f[1], and (x0 + i*dx, y0) is associated with f[i],
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// i.e., we are assuming traditional C row major order.
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// The y coordinate increases *downward*, as is traditional in 2D computer graphics.
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// This is *not* how people generally think in numerical analysis (although it *is* how they lay out matrices).
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// Providing the capability of a grid rotation is too expensive and not ergonomic; you'll need to perform any rotations at the call level.
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// For clarity, the value f(x0 + i*dx, y0 + j*dy) must be stored in the f[j*cols + i] position.
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#ifndef BOOST_MATH_INTERPOLATORS_BILINEAR_UNIFORM_HPP
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#define BOOST_MATH_INTERPOLATORS_BILINEAR_UNIFORM_HPP
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#include <utility>
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#include <memory>
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#include <boost/math/interpolators/detail/bilinear_uniform_detail.hpp>
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namespace boost::math::interpolators {
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template <class RandomAccessContainer>
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class bilinear_uniform
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{
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public:
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using Real = typename RandomAccessContainer::value_type;
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using Z = typename RandomAccessContainer::size_type;
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bilinear_uniform(RandomAccessContainer && fieldData, Z rows, Z cols, Real dx = 1, Real dy = 1, Real x0 = 0, Real y0 = 0)
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: m_imp(std::make_shared<detail::bilinear_uniform_imp<RandomAccessContainer>>(std::move(fieldData), rows, cols, dx, dy, x0, y0))
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{
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}
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Real operator()(Real x, Real y) const
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{
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return m_imp->operator()(x,y);
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}
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friend std::ostream& operator<<(std::ostream& out, bilinear_uniform<RandomAccessContainer> const & bu) {
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out << *bu.m_imp;
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return out;
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}
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private:
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std::shared_ptr<detail::bilinear_uniform_imp<RandomAccessContainer>> m_imp;
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};
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}
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#endif
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