GDALDataset::ComputeInterBandCovarianceMatrix(): optimize CPU usage

Author: rouault

autotest/gcore/gdal_stats.py

@@ -1459,7 +1459,7 @@ def test_stats_ComputeInterBandCovarianceMatrix_nodata():
     ds.GetRasterBand(2).WriteRaster(0, 0, 4, 1, b"\x02\x01\xFE\x03")
     ds.GetRasterBand(2).SetNoDataValue(254)
 
-    expected_cov_matrix = [[1, -0.5], [-0.5, 1]]
+    expected_cov_matrix = [[1, 0], [0, 1]]
 
     cov_matrix = ds.ComputeInterBandCovarianceMatrix()
     assert list(chain.from_iterable(cov_matrix)) == pytest.approx(
@@ -1476,7 +1476,7 @@ def test_stats_ComputeInterBandCovarianceMatrix_nan_value():
     ds.GetRasterBand(1).WriteRaster(0, 0, 4, 1, struct.pack("f" * 4, 1, 2, 3, math.nan))
     ds.GetRasterBand(2).WriteRaster(0, 0, 4, 1, struct.pack("f" * 4, 2, 1, math.nan, 3))
 
-    expected_cov_matrix = [[1, -0.5], [-0.5, 1]]
+    expected_cov_matrix = [[1, 0], [0, 1]]
 
     cov_matrix = ds.ComputeInterBandCovarianceMatrix()
     assert list(chain.from_iterable(cov_matrix)) == pytest.approx(
@@ -1527,7 +1527,7 @@ def test_stats_ComputeInterBandCovarianceMatrix_mask_band():
     ds.GetRasterBand(2).CreateMaskBand(0)
     ds.GetRasterBand(2).GetMaskBand().WriteRaster(0, 0, 4, 1, b"\xFF\xFF\x00\xFF")
 
-    expected_cov_matrix = [[1, -0.5], [-0.5, 1]]
+    expected_cov_matrix = [[1, 0], [0, 1]]
 
     cov_matrix = ds.ComputeInterBandCovarianceMatrix()
     assert list(chain.from_iterable(cov_matrix)) == pytest.approx(

gcore/CMakeLists.txt

@@ -64,6 +64,13 @@ add_library(
   enviutils.cpp
 )
 
+include(CheckCXXCompilerFlag)
+check_cxx_compiler_flag(-fopenmp-simd HAVE_OPENMD_SIMD)
+if (HAVE_OPENMD_SIMD)
+    target_compile_definitions(gcore PRIVATE HAVE_OPENMD_SIMD)
+    target_compile_options(gcore PRIVATE "-fopenmp-simd")
+endif()
+
 add_library(gcore_gdal_misc OBJECT gdal_misc.cpp)
 gdal_standard_includes(gcore_gdal_misc)
 add_dependencies(gcore_gdal_misc generate_gdal_version_h)