[geos-commits] [SCM] GEOS branch main updated. c2a1d40c2d86f0b6f8028d4965ffa2aef79473d7

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- Log -----------------------------------------------------------------
commit c2a1d40c2d86f0b6f8028d4965ffa2aef79473d7
Author: Sven Jensen <sven at analysis.net>
Date:   Mon Dec 1 09:24:48 2025 -0800

    SIMD vectorization of Length.cpp, up to 2.8x faster
    
    Enables the SIMD vectorization of the line-length loop when HAVE_OPEN_SIMD is defined.

diff --git a/src/algorithm/Length.cpp b/src/algorithm/Length.cpp
index 68897dac4..64087b6bc 100644
--- a/src/algorithm/Length.cpp
+++ b/src/algorithm/Length.cpp
@@ -35,22 +35,15 @@ Length::ofLine(const geom::CoordinateSequence* pts)
     }
 
     double len = 0.0;
-
-    const geom::CoordinateXY& p = pts->getAt<geom::CoordinateXY>(0);
-    double x0 = p.x;
-    double y0 = p.y;
-
+    
     for(std::size_t i = 1; i < n; i++) {
         const geom::CoordinateXY& pi = pts->getAt<geom::CoordinateXY>(i);
-        double x1 = pi.x;
-        double y1 = pi.y;
-        double dx = x1 - x0;
-        double dy = y1 - y0;
+        const geom::CoordinateXY& pi_1 = pts->getAt<geom::CoordinateXY>(i-1);
+        
+        double dx = pi.x - pi_1.x;
+        double dy = pi.y - pi_1.y;
 
         len += std::sqrt(dx * dx + dy * dy);
-
-        x0 = x1;
-        y0 = y1;
     }
     return len;
 }
@@ -63,20 +56,15 @@ Length::ofLine(const std::vector<geom::CoordinateXY>& pts)
     }
 
     double len = 0;
-    double x0 = pts[0].x;
-    double y0 = pts[0].y;
-
+    
     for(std::size_t i = 1; i < pts.size(); i++) {
         const geom::CoordinateXY& pi = pts[i];
-        double x1 = pi.x;
-        double y1 = pi.y;
-        double dx = x1 - x0;
-        double dy = y1 - y0;
+        const geom::CoordinateXY& pi_1 = pts[i-1];
+        
+        double dx = pi.x - pi_1.x;
+        double dy = pi.y - pi_1.y;
 
         len += std::sqrt(dx * dx + dy * dy);
-
-        x0 = x1;
-        y0 = y1;
     }
 
     return len;

-----------------------------------------------------------------------

Summary of changes:
 src/algorithm/Length.cpp | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)


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