reserve size

AMReX-Codes · Sep 8, 2024 · 3ab7b9d · 3ab7b9d
1 parent e1d653f
commit 3ab7b9d
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diff --git a/Src/EB/AMReX_EB_STL_utils.H b/Src/EB/AMReX_EB_STL_utils.H
@@ -109,6 +109,7 @@ private:
                                Gpu::PinnedVector<Triangle>& a_tri_pts);
 
     static void build_bvh (Triangle* begin, Triangle * end, Gpu::PinnedVector<Node>& bvh_nodes);
+    static void bvh_size (int ntri, std::size_t& nnodes);
 };
 
 }

diff --git a/Src/EB/AMReX_EB_STL_utils.cpp b/Src/EB/AMReX_EB_STL_utils.cpp
@@ -358,6 +358,9 @@ STLtools::prepare (Gpu::PinnedVector<Triangle> a_tri_pts)
     Gpu::PinnedVector<Node> bvh_nodes;
     if (m_bvh_optimization) {
         BL_PROFILE("STLtools::build_bvh");
+        std::size_t nnodes = 0;
+        bvh_size(int(a_tri_pts.size()), nnodes);
+        bvh_nodes.reserve(nnodes);
         build_bvh(a_tri_pts.data(), a_tri_pts.data()+a_tri_pts.size(), bvh_nodes);
 #ifdef AMREX_USE_GPU
         m_bvh_nodes.resize(bvh_nodes.size());
@@ -600,6 +603,23 @@ STLtools::build_bvh (Triangle* begin, Triangle* end, Gpu::PinnedVector<Node>& bv
     }
 }
 
+void
+STLtools::bvh_size (int ntri, std::size_t& nnodes)
+{
+    ++nnodes;
+
+    if (ntri <= m_bvh_max_size) { return; } // This is a leaf node
+
+    int nsplits = std::min((ntri + (m_bvh_max_size-1)) / m_bvh_max_size, m_bvh_max_splits);
+    int tsize = ntri / nsplits;
+    int nleft = ntri - tsize*nsplits;
+
+    for (int isplit = 0; isplit < nsplits; ++isplit) {
+        int child_size = (isplit < nleft) ? (tsize+1) : tsize;
+        bvh_size(child_size, nnodes);
+    }
+}
+
 void
 STLtools::fill (MultiFab& mf, IntVect const& nghost, Geometry const& geom,
                 Real outside_value, Real inside_value) const