[extensions] Automatically generated floating point filters.

extensions/example/Jamfile

@@ -13,3 +13,4 @@ project boost-geometry-examples-extensions
     ;
 
 build-project gis ;
+build-project generic_robust_predicates ;

extensions/example/generic_robust_predicates/Jamfile

@@ -0,0 +1,12 @@
+# Boost.Geometry (aka GGL, Generic Geometry Library)
+
+# Use, modification and distribution is subject to the Boost Software License,
+# Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+
+project boost-geometry-example-extensions-generic_robust_predicates
+    :
+    ;
+
+exe static_side_2d : static_side_2d.cpp ;

extensions/example/generic_robust_predicates/static_side_2d.cpp

@@ -0,0 +1,79 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2020 Tinko Bartels, Berlin, Germany.
+
+// Contributed and/or modified by Tinko Bartels,
+//   as part of Google Summer of Code 2020 program.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+
+#define BOOST_GEOMETRY_NO_BOOST_TEST
+
+#include <iostream>
+
+#include <boost/geometry/core/cs.hpp>
+#include <boost/geometry/geometries/point.hpp>
+
+#include <boost/geometry/extensions/triangulation/strategies/cartesian/side_robust.hpp>
+#include <boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/expressions.hpp>
+#include <boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/stage_a.hpp>
+
+
+namespace bg = boost::geometry;
+using point = bg::model::point<double, 2, bg::cs::cartesian>;
+
+template <typename CalculationType>
+struct side_robust_with_static_filter
+{
+private:
+    using ct = CalculationType;
+    using expression = bg::detail::generic_robust_predicates::orient2d;
+    using filter = bg::detail::generic_robust_predicates::stage_a_static
+            <
+                expression,
+                ct
+            >;
+    filter m_filter;
+public:
+    side_robust_with_static_filter(ct x_max, ct y_max, ct x_min, ct y_min)
+        : m_filter(x_max, y_max, x_max, y_max, x_max, y_max,
+                   x_min, y_min, x_min, y_min, x_min, y_min) {};
+
+    template
+    <
+        typename P1,
+        typename P2,
+        typename P  
+    >
+    inline int apply(P1 const& p1, P2 const& p2, P const& p) const
+    {
+        int sign = m_filter.apply(bg::get<0>(p1),
+                                  bg::get<1>(p1),
+                                  bg::get<0>(p2),
+                                  bg::get<1>(p2),
+                                  bg::get<0>(p),
+                                  bg::get<1>(p));
+        if(sign != bg::detail::generic_robust_predicates::sign_uncertain)
+        {
+            return sign;
+        }
+        else
+        {
+            //fallback if filter fails.
+            return bg::strategy::side::side_robust<double>::apply(p1, p2, p);
+        }
+    }
+};
+
+int main(int argc, char** argv)
+{
+    point p1(0.0, 0.0);
+    point p2(1.0, 1.0);
+    point p (0.0, 1.0);
+    side_robust_with_static_filter<double> static_strategy(2.0, 2.0, 1.0, 1.0);
+    std::cout << "Side value: " << static_strategy.apply(p1, p2, p) << "\n"; 
+    return 0;
+}

extensions/test/Jamfile

@@ -28,3 +28,4 @@ build-project gis ;
 build-project iterators ;
 build-project nsphere ;
 build-project triangulation ;
+build-project generic_robust_predicates ;

extensions/test/generic_robust_predicates/Jamfile

@@ -0,0 +1,12 @@
+# Boost.Geometry (aka GGL, Generic Geometry Library)
+#
+# Use, modification and distribution is subject to the Boost Software License,
+# Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+test-suite boost-geometry-extensions-generic_robust_predicates
+    :
+    [ run approximate.cpp ]
+    [ run side3d.cpp : : : <debug-symbols>off ]
+    ;
+

extensions/test/generic_robust_predicates/approximate.cpp

@@ -0,0 +1,66 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+// Unit Test
+
+// Copyright (c) 2020 Tinko Bartels, Berlin, Germany.
+
+// Contributed and/or modified by Tinko Bartels,
+//   as part of Google Summer of Code 2020 program.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <array>
+
+#include <geometry_test_common.hpp>
+
+#include <boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/approximate.hpp>
+#include <boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/expression_tree.hpp>
+
+template <typename CalculationType>
+void test_all()
+{
+    using bg::detail::generic_robust_predicates::_1;
+    using bg::detail::generic_robust_predicates::_2;
+    using bg::detail::generic_robust_predicates::_3;
+    using bg::detail::generic_robust_predicates::_4;
+    using bg::detail::generic_robust_predicates::sum;
+    using bg::detail::generic_robust_predicates::difference;
+    using bg::detail::generic_robust_predicates::product;
+    using bg::detail::generic_robust_predicates::max;
+    using bg::detail::generic_robust_predicates::abs;
+    using bg::detail::generic_robust_predicates::post_order;
+    using bg::detail::generic_robust_predicates::approximate_value;
+    using bg::detail::generic_robust_predicates::get_approx;
+    using bg::detail::generic_robust_predicates::approximate_interim;
+    using ct = CalculationType;
+    ct r1 = approximate_value<sum<_1, _2>, ct>(
+            std::array<ct, 2>{1.0, 2.0});
+    BOOST_CHECK_EQUAL(3.0, r1);
+    ct r2 = approximate_value<max<abs<_1>, abs<_2>>, ct>(
+            std::array<ct, 2>{-10.0, 2.0});
+    BOOST_CHECK_EQUAL(10.0, r2);
+
+    using expression = product
+        <
+            difference<_1, _2>,
+            difference<_3, _4>
+        >;
+    using evals = post_order<expression>;
+    std::array<ct, boost::mp11::mp_size<evals>::value> r;
+    std::array<ct, 4> input {5.0, 3.0, 2.0, 8.0};
+    approximate_interim<evals, evals, ct>(r, input);
+    ct r3 = get_approx<evals, typename expression::left, ct>(r, input);
+    BOOST_CHECK_EQUAL(2.0, r3);
+    ct r4 = get_approx<evals, typename expression::right, ct>(r, input);
+    BOOST_CHECK_EQUAL(-6.0, r4);
+    ct r5 = get_approx<evals, expression, ct>(r, input);
+    BOOST_CHECK_EQUAL(-12.0, r5);
+}
+
+
+int test_main(int, char* [])
+{
+    test_all<double>();
+    return 0;
+}

extensions/test/generic_robust_predicates/side3d.cpp

@@ -0,0 +1,76 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+// Unit Test
+
+// Copyright (c) 2020 Tinko Bartels, Berlin, Germany.
+
+// Contributed and/or modified by Tinko Bartels,
+//   as part of Google Summer of Code 2020 program.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <array>
+
+#include <geometry_test_common.hpp>
+
+#include <boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/expressions.hpp>
+#include <boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/stage_a.hpp>
+
+template <typename CalculationType>
+void test_all()
+{
+    using bg::detail::generic_robust_predicates::orient3d;
+    using bg::detail::generic_robust_predicates::stage_a_semi_static;
+    using bg::detail::generic_robust_predicates::stage_a_almost_static;
+    using bg::detail::generic_robust_predicates::stage_a_static;
+    using ct = CalculationType;
+    using semi_static = stage_a_semi_static<orient3d, ct>;
+    BOOST_CHECK_EQUAL(1,
+                      semi_static::apply(1, 0, 0,
+                                         0, 1, 0,
+                                         1, 1, 0,
+                                         0, 0, 1));
+    BOOST_CHECK_EQUAL(-1,
+                      semi_static::apply(1, 0, 0,       
+                                         0, 1, 0,                
+                                         1, 1, 0,                
+                                         0, 0, -1));
+    BOOST_CHECK_EQUAL(0,
+                      semi_static::apply(1, 0, 0,       
+                                         0, 1, 0,                
+                                         1, 1, 0,                
+                                         0, 0, 0));
+    stage_a_static<orient3d, ct> stat(10, 10, 10,
+                                      10, 10, 10,
+                                      10, 10, 10,
+                                      10, 10, 10,
+                                       0,  0,  0,
+                                       0,  0,  0,
+                                       0,  0,  0,
+                                       0,  0,  0);
+    BOOST_CHECK_EQUAL(1, stat.apply(1, 0, 0,
+                                    0, 1, 0,
+                                    1, 1, 0,
+                                    0, 0, 1));
+
+    stage_a_static<orient3d, ct> pessimistic(1e40, 1e40, 1e40,
+                                             1e40, 1e40, 1e40,
+                                             1e40, 1e40, 1e40,
+                                             1e40, 1e40, 1e40, 
+                                             0,    0,    0,  
+                                             0,    0,    0, 
+                                             0,    0,    0,
+                                             0,    0,    0);
+    BOOST_CHECK_EQUAL(bg::detail::generic_robust_predicates::sign_uncertain,
+                      pessimistic.apply(1, 0, 0,
+                                        0, 1, 0,
+                                        1, 1, 0,
+                                        0, 0, 1));
+}
+
+int test_main(int, char* [])
+{
+    test_all<double>();
+    return 0;
+}

include/boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/almost_static_filter.hpp

@@ -0,0 +1,133 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2020 Tinko Bartels, Berlin, Germany.
+
+// Contributed and/or modified by Tinko Bartels,
+//   as part of Google Summer of Code 2020 program.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_GEOMETRY_EXTENSIONS_GENERIC_ROBUST_PREDICATES_STRATEGIES_CARTESIAN_DETAIL_ALMOST_STATIC_FILTER_HPP
+#define BOOST_GEOMETRY_EXTENSIONS_GENERIC_ROBUST_PREDICATES_STRATEGIES_CARTESIAN_DETAIL_ALMOST_STATIC_FILTER_HPP
+
+#include <array>
+#include <algorithm>
+#include <limits>
+
+#include <boost/geometry/extensions/generic_robust_predicates/strategies/cartesian/detail/expression_tree.hpp>
+
+namespace boost { namespace geometry
+{
+
+namespace detail { namespace generic_robust_predicates
+{
+
+template <typename Filter, std::size_t N, std::size_t End>
+struct make_filter_impl
+{
+    template <typename ExtremaArray, typename ...Reals>
+    static Filter apply(const ExtremaArray& extrema, const Reals&... args)
+    {
+        return make_filter_impl<Filter, N + 1, End>
+            ::apply(extrema, args..., extrema[N]);
+    }
+};
+
+template <typename Filter, std::size_t End>
+struct make_filter_impl<Filter, End, End>
+{
+    template <typename ExtremaArray, typename ...Reals>
+    static Filter apply(const ExtremaArray& extrema, const Reals&... args)
+    {
+        Filter f(args...);
+        return f;
+    }
+};
+
+template
+<
+    typename Expression,
+    typename CalculationType,
+    typename StaticFilter
+>
+class almost_static_filter
+{
+private:
+    using expression_max_argn = max_argn<Expression>;
+    using ct = CalculationType;
+    using extrema_array = std::array<ct, 2 * expression_max_argn::value>;
+    extrema_array m_extrema;
+    StaticFilter m_filter;
+public:
+    const StaticFilter& filter() const { return m_filter; }
+    inline almost_static_filter()
+    {
+        std::fill(m_extrema.begin(),
+                  m_extrema.begin() + m_extrema.size() / 2,
+                  -std::numeric_limits<ct>::infinity());
+        std::fill(m_extrema.begin() + m_extrema.size() / 2,
+                  m_extrema.end(),
+                  std::numeric_limits<ct>::infinity());
+    }
+    template <typename ...Reals>
+    int apply(const Reals&... args) const
+    {
+        return m_filter.apply(args...);
+    }
+
+    template <typename ...Reals>
+    inline void update_extrema(const Reals&... args)
+    {
+        std::array<ct, sizeof...(Reals)> input {{ static_cast<ct>(args)... }};
+        for(int i = 0; i < m_extrema.size() / 2; ++i)
+        {
+            m_extrema[i] = std::max(m_extrema[i], input[i]);
+        }
+        for(int i = m_extrema.size() / 2; i < m_extrema.size(); ++i)
+        {
+            m_extrema[i] = std::min(m_extrema[i], input[i]);
+        }
+    }
+
+    template <typename ...Reals>
+    inline bool update_extrema_check(const Reals&... args)
+    {
+        bool changed = false;
+        std::array<ct, sizeof...(Reals)> input {{ static_cast<ct>(args)... }};
+        for(int i = 0; i < m_extrema.size() / 2; ++i)
+        {
+            if(input[i] > m_extrema[i])
+            {
+                changed = true;
+                m_extrema[i] = input[i];
+            }
+        }
+        for(int i = m_extrema.size() / 2; i < m_extrema.size(); ++i)
+        {
+            if(input[i] < m_extrema[i])
+            {
+                changed = true;
+                m_extrema[i] = input[i];
+            }
+        }
+        return changed;
+    }
+
+    inline void update_filter()
+    {
+        m_filter = make_filter_impl
+                <
+                    StaticFilter,
+                    0,
+                    2 * expression_max_argn::value
+                >::apply(m_extrema);
+    }
+};
+
+}} // namespace detail::generic_robust_predicates
+
+}} // namespace boost::geometry
+
+#endif // BOOST_GEOMETRY_EXTENSIONS_GENERIC_ROBUST_PREDICATES_STRATEGIES_CARTESIAN_DETAIL_ALMOST_STATIC_FILTER_HPP