Alternate polygonToCells algorithm

CHANGELOG.md

@@ -7,6 +7,7 @@ The public API of this library consists of the functions declared in file
 
 ## [Unreleased]
 ### Changed
+- Replace internal algorithm for `polygonToCells` with a new version that is more memory-efficient (#785)
 - Reorganize tests into public / internal. (#762)
 - Performance enhancement for aarch64, should not affect other platforms (#790, #792)
 

CMakeLists.txt

@@ -125,6 +125,7 @@ set(LIB_SOURCE_FILES
     src/h3lib/include/bbox.h
     src/h3lib/include/polygon.h
     src/h3lib/include/polygonAlgos.h
+    src/h3lib/include/polyfill.h
     src/h3lib/include/h3Index.h
     src/h3lib/include/directedEdge.h
     src/h3lib/include/latLng.h
@@ -146,6 +147,7 @@ set(LIB_SOURCE_FILES
     src/h3lib/lib/coordijk.c
     src/h3lib/lib/bbox.c
     src/h3lib/lib/polygon.c
+    src/h3lib/lib/polyfill.c
     src/h3lib/lib/h3Index.c
     src/h3lib/lib/vec2d.c
     src/h3lib/lib/vec3d.c
@@ -192,7 +194,9 @@ set(OTHER_SOURCE_FILES
     src/apps/testapps/testVertexGraphInternal.c
     src/apps/testapps/testCompactCells.c
     src/apps/testapps/testPolygonToCells.c
+    src/apps/testapps/testPolygonToCellsExperimental.c
     src/apps/testapps/testPolygonToCellsReported.c
+    src/apps/testapps/testPolygonToCellsReportedExperimental.c
     src/apps/testapps/testPentagonIndexes.c
     src/apps/testapps/testGridDisk.c
     src/apps/testapps/testGridDiskInternal.c
@@ -209,6 +213,7 @@ set(OTHER_SOURCE_FILES
     src/apps/testapps/testCellToLatLng.c
     src/apps/testapps/testCellToCenterChild.c
     src/apps/testapps/testCellToChildren.c
+    src/apps/testapps/testCellToBBoxExhaustive.c
     src/apps/testapps/testCellToChildPos.c
     src/apps/testapps/testGetIcosahedronFaces.c
     src/apps/testapps/testLatLng.c
@@ -220,6 +225,7 @@ set(OTHER_SOURCE_FILES
     src/apps/testapps/testVertexInternal.c
     src/apps/testapps/testVertexExhaustive.c
     src/apps/testapps/testPolygonInternal.c
+    src/apps/testapps/testPolyfillInternal.c
     src/apps/testapps/testVec2dInternal.c
     src/apps/testapps/testVec3dInternal.c
     src/apps/testapps/testDirectedEdge.c
@@ -270,6 +276,7 @@ set(OTHER_SOURCE_FILES
     src/apps/fuzzers/fuzzerInternalAlgos.c
     src/apps/fuzzers/fuzzerInternalCoordIjk.c
     src/apps/benchmarks/benchmarkPolygonToCells.c
+    src/apps/benchmarks/benchmarkPolygonToCellsExperimental.c
     src/apps/benchmarks/benchmarkPolygon.c
     src/apps/benchmarks/benchmarkCellsToLinkedMultiPolygon.c
     src/apps/benchmarks/benchmarkCellToChildren.c
@@ -566,6 +573,7 @@ if(BUILD_BENCHMARKS)
     add_h3_benchmark(benchmarkCellsToLinkedMultiPolygon src/apps/benchmarks/benchmarkCellsToLinkedMultiPolygon.c)
     add_h3_benchmark(benchmarkCellToChildren src/apps/benchmarks/benchmarkCellToChildren.c)
     add_h3_benchmark(benchmarkPolygonToCells src/apps/benchmarks/benchmarkPolygonToCells.c)
+    add_h3_benchmark(benchmarkPolygonToCellsExperimental src/apps/benchmarks/benchmarkPolygonToCellsExperimental.c)
     if(ENABLE_REQUIRES_ALL_SYMBOLS)
         add_h3_benchmark(benchmarkPolygon src/apps/benchmarks/benchmarkPolygon.c)
     endif()

CMakeTests.cmake

@@ -186,7 +186,9 @@ add_h3_test(testCellsToLinkedMultiPolygon src/apps/testapps/testCellsToLinkedMul
 add_h3_test(testH3SetToVertexGraphInternal src/apps/testapps/testH3SetToVertexGraphInternal.c)
 add_h3_test(testLinkedGeoInternal src/apps/testapps/testLinkedGeoInternal.c)
 add_h3_test(testPolygonToCells src/apps/testapps/testPolygonToCells.c)
+add_h3_test(testPolygonToCellsExperimental src/apps/testapps/testPolygonToCellsExperimental.c)
 add_h3_test(testPolygonToCellsReported src/apps/testapps/testPolygonToCellsReported.c)
+add_h3_test(testPolygonToCellsReportedExperimental src/apps/testapps/testPolygonToCellsReportedExperimental.c)
 add_h3_test(testVertexGraphInternal src/apps/testapps/testVertexGraphInternal.c)
 add_h3_test(testDirectedEdge src/apps/testapps/testDirectedEdge.c)
 add_h3_test(testLatLng src/apps/testapps/testLatLng.c)
@@ -195,6 +197,7 @@ add_h3_test(testBBoxInternal src/apps/testapps/testBBoxInternal.c)
 add_h3_test(testVertex src/apps/testapps/testVertex.c)
 add_h3_test(testVertexInternal src/apps/testapps/testVertexInternal.c)
 add_h3_test(testPolygonInternal src/apps/testapps/testPolygonInternal.c)
+add_h3_test(testPolyfillInternal src/apps/testapps/testPolyfillInternal.c)
 add_h3_test(testVec2dInternal src/apps/testapps/testVec2dInternal.c)
 add_h3_test(testVec3dInternal src/apps/testapps/testVec3dInternal.c)
 add_h3_test(testCellToLocalIj src/apps/testapps/testCellToLocalIj.c)
@@ -223,6 +226,7 @@ add_h3_test(testCellToLocalIjExhaustive src/apps/testapps/testCellToLocalIjExhau
 add_h3_test(testGridPathCellsExhaustive src/apps/testapps/testGridPathCellsExhaustive.c)
 add_h3_test(testGridDistanceExhaustive src/apps/testapps/testGridDistanceExhaustive.c)
 add_h3_test(testH3CellAreaExhaustive src/apps/testapps/testH3CellAreaExhaustive.c)
+add_h3_test(testCellToBBoxExhaustive src/apps/testapps/testCellToBBoxExhaustive.c)
 
 add_h3_cli_test(testCliCellToLatLng "cellToLatLng -c 8928342e20fffff" "37.5012466151, -122.5003039349")
 add_h3_cli_test(testCliLatLngToCell "latLngToCell --lat 20 --lng 123 -r 2" "824b9ffffffffff")

README.md

@@ -112,13 +112,13 @@ You can run a faster test suite that excludes the most expensive tests with `mak
 
 #### Coverage
 
-You can generate a code coverage report if `lcov` is installed, and if the project was built with the `CMAKE_BUILD_TYPE=Debug` option.
+You can generate a code coverage report if `lcov` is installed, and if the project was built with the `CMAKE_BUILD_TYPE=Debug` and `ENABLE_COVERAGE=ON` options.
 For example, from a clean repository, you could run:
 
 ```
 mkdir build
 cd build
-cmake -DCMAKE_BUILD_TYPE=Debug ..
+cmake -DCMAKE_BUILD_TYPE=Debug -DENABLE_COVERAGE=ON ..
 make
 make coverage
 ```

src/apps/applib/include/utility.h

@@ -22,6 +22,7 @@
 
 #include <stdio.h>
 
+#include "bbox.h"
 #include "coordijk.h"
 #include "h3api.h"
 
@@ -46,6 +47,8 @@ void geoPrintNoFmt(const LatLng *p);
 void geoPrintlnNoFmt(const LatLng *p);
 void cellBoundaryPrint(const CellBoundary *b);
 void cellBoundaryPrintln(const CellBoundary *b);
+void bboxPrint(const BBox *bbox);
+void bboxPrintln(const BBox *bbox);
 
 void randomGeo(LatLng *p);
 

src/apps/applib/lib/utility.c

@@ -118,6 +118,18 @@ void cellBoundaryPrintln(const CellBoundary *b) {
     printf("}\n");
 }
 
+void bboxPrint(const BBox *bbox) {
+    printf(
+        "bbox {%.9lf, %.9lf, %.9lf, %.9lf}", H3_EXPORT(radsToDegs)(bbox->north),
+        H3_EXPORT(radsToDegs)(bbox->south), H3_EXPORT(radsToDegs)(bbox->east),
+        H3_EXPORT(radsToDegs)(bbox->west));
+}
+
+void bboxPrintln(const BBox *bbox) {
+    bboxPrint(bbox);
+    printf("\n");
+}
+
 /**
  * Apply callback for every unidirectional edge at the given resolution.
  */

src/apps/benchmarks/benchmarkPolygonToCellsExperimental.c

@@ -0,0 +1,146 @@
+/*
+ * Copyright 2017, 2020-2021 Uber Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "algos.h"
+#include "benchmark.h"
+#include "h3api.h"
+#include "polyfill.h"
+
+// Fixtures
+LatLng sfVerts[] = {
+    {0.659966917655, -2.1364398519396},  {0.6595011102219, -2.1359434279405},
+    {0.6583348114025, -2.1354884206045}, {0.6581220034068, -2.1382437718946},
+    {0.6594479998527, -2.1384597563896}, {0.6599990002976, -2.1376771158464}};
+GeoLoop sfGeoLoop;
+GeoPolygon sfGeoPolygon;
+
+LatLng alamedaVerts[] = {{0.6597959342671712, -2.133241848488897},
+                         {0.6597959348850178, -2.133241848495878},
+                         {0.6598352639563587, -2.1331688423977755},
+                         {0.6601346536539207, -2.13270417124178},
+                         {0.6601594763880223, -2.1326680320633344},
+                         {0.6601512007732382, -2.1326594176574534},
+                         {0.6598535076212304, -2.1323049630593562},
+                         {0.6596565748646488, -2.132069889917591},
+                         {0.6594645035394391, -2.131843148468039},
+                         {0.6593438094209757, -2.1316994860539844},
+                         {0.6591174422311021, -2.131429776816562},
+                         {0.658849344286881, -2.1311111485483867},
+                         {0.6588348862079956, -2.1310988536794455},
+                         {0.6586273138317915, -2.131668420800747},
+                         {0.6583729538174264, -2.132370426573979},
+                         {0.6582479206289285, -2.132718691911663},
+                         {0.6582322393220743, -2.1327614200082317},
+                         {0.6583003647098981, -2.132837478687196},
+                         {0.6584457274847966, -2.132827956758973},
+                         {0.6585526679060995, -2.1330231566043203},
+                         {0.6587379099516777, -2.1331602726234538},
+                         {0.6587273684736642, -2.1332676321559063},
+                         {0.6584638025857692, -2.133305719954319},
+                         {0.6583545950288919, -2.1334323622944993},
+                         {0.6584427148370682, -2.1335885223323947},
+                         {0.6584715236640714, -2.133649780409862},
+                         {0.6584715242505019, -2.133649780481421},
+                         {0.658474662092443, -2.1336459234695804},
+                         {0.6591666596433436, -2.1348354004882926},
+                         {0.6591809355063646, -2.1348424115474565},
+                         {0.6593477498700266, -2.1351460576998926},
+                         {0.6597155087395117, -2.1351049454274},
+                         {0.6597337410387994, -2.135113899444683},
+                         {0.6598277083823935, -2.1351065432309517},
+                         {0.659837290351688, -2.1350919904836627},
+                         {0.6598391300107502, -2.1350911731005957},
+                         {0.6598335712627461, -2.1350732321630828},
+                         {0.6597162034032434, -2.134664026354221},
+                         {0.6596785831942451, -2.134651647657116},
+                         {0.6596627824684727, -2.13458880305965},
+                         {0.6596785832500957, -2.134530719130462},
+                         {0.6596093592822273, -2.13428052987356},
+                         {0.6596116166352313, -2.134221493755564},
+                         {0.6595973199434513, -2.134146270344056},
+                         {0.6595536764042369, -2.1340805688066653},
+                         {0.6594611172376618, -2.133753252031165},
+                         {0.6594829406269346, -2.1337342082305697},
+                         {0.6594897134102581, -2.1337104032834757},
+                         {0.6597920983773051, -2.1332343063312775},
+                         {0.6597959342671712, -2.133241848488897}};
+GeoLoop alamedaGeoLoop;
+GeoPolygon alamedaGeoPolygon;
+
+LatLng southernVerts[] = {{0.6367481147484843, -2.1290865397798906},
+                          {0.6367481152301953, -2.129086539469222},
+                          {0.6367550754426818, -2.128887436716856},
+                          {0.6367816002113981, -2.1273204058681094},
+                          {0.6380814125349741, -2.127201274803692},
+                          {0.6388614350074809, -2.12552061082428},
+                          {0.6393520289210095, -2.124274316938293},
+                          {0.639524834205869, -2.122168447308359},
+                          {0.6405714857447717, -2.122083222593005},
+                          {0.640769478635285, -2.120979885974894},
+                          {0.6418936996869471, -2.1147667448862255},
+                          {0.6419094141707652, -2.1146521242709584},
+                          {0.6269997808948107, -2.1038647304637257},
+                          {0.6252080524974937, -2.1195521728170457},
+                          {0.626379700264057, -2.1203708632511162},
+                          {0.6282200029232767, -2.1210412050690723},
+                          {0.6283657301211779, -2.1219496416754393},
+                          {0.6305651783819565, -2.123628532238016},
+                          {0.6308259852882764, -2.124225549648211},
+                          {0.6317049665784865, -2.124887756638367},
+                          {0.6323403882676475, -2.1266205835454053},
+                          {0.6334397909415498, -2.1277211741619553},
+                          {0.6367481147484843, -2.1290865397798906}};
+GeoLoop southernGeoLoop;
+GeoPolygon southernGeoPolygon;
+
+BEGIN_BENCHMARKS();
+
+sfGeoLoop.numVerts = 6;
+sfGeoLoop.verts = sfVerts;
+sfGeoPolygon.geoloop = sfGeoLoop;
+
+alamedaGeoLoop.numVerts = 50;
+alamedaGeoLoop.verts = alamedaVerts;
+alamedaGeoPolygon.geoloop = alamedaGeoLoop;
+
+southernGeoLoop.numVerts = 23;
+southernGeoLoop.verts = southernVerts;
+southernGeoPolygon.geoloop = southernGeoLoop;
+
+int64_t numHexagons;
+H3Index *hexagons;
+
+BENCHMARK(polygonToCellsSF, 500, {
+    H3_EXPORT(maxPolygonToCellsSize)(&sfGeoPolygon, 9, 0, &numHexagons);
+    hexagons = calloc(numHexagons, sizeof(H3Index));
+    H3_EXPORT(polygonToCellsExperimental)(&sfGeoPolygon, 9, 0, hexagons);
+    free(hexagons);
+});
+
+BENCHMARK(polygonToCellsAlameda, 500, {
+    H3_EXPORT(maxPolygonToCellsSize)(&alamedaGeoPolygon, 9, 0, &numHexagons);
+    hexagons = calloc(numHexagons, sizeof(H3Index));
+    H3_EXPORT(polygonToCellsExperimental)(&alamedaGeoPolygon, 9, 0, hexagons);
+    free(hexagons);
+});
+
+BENCHMARK(polygonToCellsSouthernExpansion, 10, {
+    H3_EXPORT(maxPolygonToCellsSize)(&southernGeoPolygon, 9, 0, &numHexagons);
+    hexagons = calloc(numHexagons, sizeof(H3Index));
+    H3_EXPORT(polygonToCellsExperimental)(&southernGeoPolygon, 9, 0, hexagons);
+    free(hexagons);
+});
+
+END_BENCHMARKS();