Merge pull request #3337 from lightmare/normalize-angle

speed up util::normalize_angle for large values

benchmark/build.py

@@ -18,40 +18,19 @@ test_env.Append(CPPDEFINES = env['LIBMAPNIK_DEFINES'])
 if test_env['HAS_CAIRO']:
     test_env.PrependUnique(CPPPATH=test_env['CAIRO_CPPPATHS'])
     test_env.Append(CPPDEFINES = '-DHAVE_CAIRO')
+test_env.PrependUnique(CPPPATH='include', delete_existing=True)
 test_env['LINKFLAGS'] = copy(test_env['LIBMAPNIK_LINKFLAGS'])
 if env['PLATFORM'] == 'Darwin':
     test_env.Append(LINKFLAGS='-F/ -framework CoreFoundation')
 
 test_env_local = test_env.Clone()
 
-#benchmarks = glob.glob('test*cpp')
-benchmarks = [
-    #"test_array_allocation.cpp",
-    #"test_png_encoding1.cpp",
-    #"test_png_encoding2.cpp",
-    #"test_to_string1.cpp",
-    #"test_to_string2.cpp",
-    #"test_to_bool.cpp",
-    #"test_to_double.cpp",
-    #"test_to_int.cpp",
-    #"test_utf_encoding.cpp"
-    "test_polygon_clipping.cpp",
-    #"test_polygon_clipping_rendering.cpp",
-    "test_proj_transform1.cpp",
-    "test_expression_parse.cpp",
-    "test_face_ptr_creation.cpp",
-    "test_font_registration.cpp",
-    "test_rendering.cpp",
-    "test_rendering_shared_map.cpp",
-    "test_offset_converter.cpp",
-    "test_marker_cache.cpp",
-    "test_quad_tree.cpp",
-    "test_noop_rendering.cpp",
-    "test_getline.cpp",
-#    "test_numeric_cast_vs_static_cast.cpp",
-]
-for cpp_test in benchmarks:
-    test_program = test_env_local.Program('out/'+cpp_test.replace('.cpp',''), source=[cpp_test])
+benchmarks = glob.glob("src/*.cpp")
+
+for src in benchmarks:
+    name, ext = os.path.splitext(os.path.basename(src))
+    out = os.path.join("out", name)
+    test_program = test_env_local.Program(out, source=[src])
     if 'install' in COMMAND_LINE_TARGETS:
         env.Alias('install',test_program)
     #Depends(test_program, env.subst('../src/%s' % env['MAPNIK_LIB_NAME']))

benchmark/include/bench_framework.hpp

@@ -12,6 +12,7 @@
 #include <chrono>
 #include <cmath> // log10, round
 #include <cstdio> // snprintf
+#include <iomanip>
 #include <iostream>
 #include <set>
 #include <sstream>
@@ -239,14 +240,19 @@ int run(T const& test_runner, std::string const& name)
         big_number_fmt itersf(4, total_iters);
         big_number_fmt ips(5, total_iters / seconds<double>(elapsed_nonzero).count());
 
+        std::clog << std::left << std::setw(43) << name;
+        std::clog << std::resetiosflags(std::ios::adjustfield);
+        if (num_threads > 0) {
+            std::clog << ' ' << std::setw(3) << num_threads
+                << " worker" << (num_threads > 1 ? "s" : " ");
+        }
+        else {
+            std::clog << " main thread";
+        }
         std::snprintf(msg, sizeof(msg),
-                "%-43s %3zu thread(s) %*.0f%s iters %6.0f milliseconds %*.0f%s i/s\n",
-                name.c_str(),
-                num_threads,
-                itersf.w, itersf.v, itersf.u,
-                dur_total,
-                ips.w, ips.v, ips.u
-                );
+                " %*.0f%s iters %6.0f milliseconds %*.0f%s i/t/s\n",
+                itersf.w, itersf.v, itersf.u, dur_total,
+                ips.w, ips.v, ips.u);
         std::clog << msg;
         return 0;
     }

benchmark/run

@@ -10,7 +10,7 @@ function run {
     local threads="$2"
     local iters="$3"
     shift 3
-    $runner --threads 1 --iterations $iters "$@"
+    $runner --threads 0 --iterations $iters "$@"
     if test $threads -gt 0; then
         $runner --threads $threads --iterations $((iters/threads)) "$@"
     fi
@@ -28,6 +28,7 @@ run test_expression_parse 10 10000
 run test_face_ptr_creation 10 1000
 run test_font_registration 10 100
 run test_offset_converter 10 1000
+#run normalize_angle 0 1000000 --min-duration=0.2
 
 # commented since this is really slow on travis
 : '

benchmark/src/normalize_angle.cpp

@@ -0,0 +1,69 @@
+#include "bench_framework.hpp"
+
+#include <mapnik/util/math.hpp>
+
+template <typename T>
+struct bench_func : benchmark::test_case
+{
+    T (* const func_)(T);
+    T const value_;
+
+    bench_func(mapnik::parameters const& params, T (*func)(T), T value)
+        : test_case(params), func_(func), value_(value) {}
+
+    bool validate() const { return true; }
+
+    bool operator() () const
+    {
+        for (auto i = this->iterations_; i-- > 0; )
+        {
+            func_(value_);
+        }
+        return true;
+    }
+};
+
+#define BENCH_FUNC1(func, value) \
+        run<bench_func<double>>(#func "(" #value ")", func, value)
+
+int main(int argc, char** argv)
+{
+    return benchmark::sequencer(argc, argv)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +3)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +6)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +9)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +12)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +15)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +20)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +30)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +40)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +50)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +70)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +90)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +110)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +130)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +157)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +209)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +314)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +628)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, +942)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -3)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -6)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -9)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -12)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -15)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -20)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -30)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -40)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -50)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -70)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -90)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -110)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -130)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -157)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -209)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -314)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -628)
+        .BENCH_FUNC1(mapnik::util::normalize_angle, -942)
+        .done();
+}

include/mapnik/util/math.hpp

@@ -27,9 +27,11 @@
 
 namespace mapnik { namespace util {
 
+constexpr double pi = 3.1415926535897932384626433832795;
+constexpr double tau = 6.283185307179586476925286766559;
+
 MAPNIK_DECL double normalize_angle(double angle);
 
 }}
 
 #endif
-

src/math.cpp

@@ -22,7 +22,6 @@
 
 // mapnik
 #include <mapnik/util/math.hpp>
-#include <mapnik/global.hpp>
 
 // stl
 #include <cmath>
@@ -33,13 +32,26 @@ namespace util {
 
     double normalize_angle(double angle)
     {
-        while (angle >= M_PI)
+        if (angle > pi)
         {
-            angle -= 2.0 * M_PI;
+            if (angle > 16 * tau)
+            {
+                // the angle is too large; better compute the remainder
+                // directly to avoid subtracting circles ad infinitum
+                return std::remainder(angle, tau);
+            }
+            // std::remainder would take longer than a few subtractions
+            while ((angle -= tau) > pi)
+                ;
         }
-        while (angle < -M_PI)
+        else if (angle < -pi)
         {
-            angle += 2.0 * M_PI;
+            if (angle < -16 * tau)
+            {
+                return std::remainder(angle, tau);
+            }
+            while ((angle += tau) < -pi)
+                ;
         }
         return angle;
     }