ceph/src/boost/boost/math/interpolators/bilinear_uniform.hpp

   1 // Copyright Nick Thompson, 2021
   2 // Use, modification and distribution are subject to the
   3 // Boost Software License, Version 1.0.
   4 // (See accompanying file LICENSE_1_0.txt
   5 // or copy at http://www.boost.org/LICENSE_1_0.txt)
   6
   7 // This implements bilinear interpolation on a uniform grid.
   8 // 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])
   9 // The point (x0 + dx, y0) is associated with f[1], and (x0 + i*dx, y0) is associated with f[i],
  10 // i.e., we are assuming traditional C row major order.
  11 // The y coordinate increases *downward*, as is traditional in 2D computer graphics.
  12 // This is *not* how people generally think in numerical analysis (although it *is* how they lay out matrices).
  13 // Providing the capability of a grid rotation is too expensive and not ergonomic; you'll need to perform any rotations at the call level.
  14
  15 // For clarity, the value f(x0 + i*dx, y0 + j*dy) must be stored in the f[j*cols + i] position.
  16
  17 #ifndef BOOST_MATH_INTERPOLATORS_BILINEAR_UNIFORM_HPP
  18 #define BOOST_MATH_INTERPOLATORS_BILINEAR_UNIFORM_HPP
  19
  20 #include <utility>
  21 #include <memory>
  22 #include <boost/math/interpolators/detail/bilinear_uniform_detail.hpp>
  23
  24 namespace boost::math::interpolators {
  25
  26 template <class RandomAccessContainer>
  27 class bilinear_uniform
  28 {
  29 public:
  30     using Real = typename RandomAccessContainer::value_type;
  31     using Z = typename RandomAccessContainer::size_type;
  32
  33     bilinear_uniform(RandomAccessContainer && fieldData, Z rows, Z cols, Real dx = 1, Real dy = 1, Real x0 = 0, Real y0 = 0)
  34     : m_imp(std::make_shared<detail::bilinear_uniform_imp<RandomAccessContainer>>(std::move(fieldData), rows, cols, dx, dy, x0, y0))
  35     {
  36     }
  37
  38     Real operator()(Real x, Real y) const
  39     {
  40         return m_imp->operator()(x,y);
  41     }
  42
  43
  44     friend std::ostream& operator<<(std::ostream& out, bilinear_uniform<RandomAccessContainer> const & bu) {
  45         out << *bu.m_imp;
  46         return out;
  47     }
  48
  49 private:
  50     std::shared_ptr<detail::bilinear_uniform_imp<RandomAccessContainer>> m_imp;
  51 };
  52
  53 }
  54 #endif