From ddc17818b089b0d242e2f1975a733a4833b2ee7f Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@klayout.de>
Date: Sat, 4 Apr 2026 19:34:54 +0200
Subject: [PATCH] Bugfix + tests added

---
 src/db/db/dbHierarchyBuilder.cc            |   2 +-
 src/db/unit_tests/dbDeepShapeStoreTests.cc | 108 +++++++++++++++++++++
 2 files changed, 109 insertions(+), 1 deletion(-)

diff --git a/src/db/db/dbHierarchyBuilder.cc b/src/db/db/dbHierarchyBuilder.cc
index d5086951c..4049f68c3 100644
--- a/src/db/db/dbHierarchyBuilder.cc
+++ b/src/db/db/dbHierarchyBuilder.cc
@@ -408,7 +408,7 @@ HierarchyBuilder::new_inst (const RecursiveShapeIterator *iter, const db::CellIn
           db::box_convert<db::CellInst> bc (*iter->layout ());
           auto a1 = bc (inst.object ()).area ();
           auto aa = inst.bbox (bc).area ();
-          if (a1 * m_sparse_array_limit < aa) {
+          if (a1 * m_sparse_array_limit * inst.size () < aa) {
             resolve = true;
           }
         }
diff --git a/src/db/unit_tests/dbDeepShapeStoreTests.cc b/src/db/unit_tests/dbDeepShapeStoreTests.cc
index 102d26994..ea0acbde1 100644
--- a/src/db/unit_tests/dbDeepShapeStoreTests.cc
+++ b/src/db/unit_tests/dbDeepShapeStoreTests.cc
@@ -376,3 +376,111 @@ TEST(8_RestoreWithCellSelection3)
   db::compare_layouts (_this, ly, tl::testdata () + "/algo/dss_bug3_au.gds");
 }
 
+TEST(9_sparse_array_limit)
+{
+  db::Layout ly;
+
+  {
+    std::string fn (tl::testdata ());
+    fn += "/algo/dss_sparse_array.gds";
+    tl::InputStream stream (fn);
+    db::Reader reader (stream);
+    reader.read (ly);
+  }
+
+  unsigned int l2 = ly.get_layer (db::LayerProperties (2, 0));
+  unsigned int l1 = ly.get_layer (db::LayerProperties (1, 0));
+  unsigned int l12 = ly.get_layer (db::LayerProperties (12, 0));
+  unsigned int l11 = ly.get_layer (db::LayerProperties (11, 0));
+
+  db::Cell &top_cell = ly.cell (*ly.begin_top_down ());
+
+  db::RecursiveShapeIterator in_it1 (ly, top_cell, l1);
+  db::RecursiveShapeIterator in_it2 (ly, top_cell, l2);
+
+  {
+    db::DeepShapeStore dss;
+    EXPECT_EQ (dss.sparse_array_limit (), -1.0);
+
+    db::Region in_region1 (in_it1, dss);
+    db::Region in_region2 (in_it2, dss);
+
+    const db::Layout &dss_ly = dss.layout (0);
+    const db::Cell &dss_top_cell = dss_ly.cell (*dss_ly.begin_top_down ());
+    size_t n_inst = 0;
+    size_t n_total = 0;
+    for (auto i = dss_top_cell.begin (); ! i.at_end (); ++i) {
+      ++n_inst;
+      n_total += i->size ();
+    }
+
+    //  2 arrays, 1 single inst
+    EXPECT_EQ (n_inst, size_t (3));
+    EXPECT_EQ (n_total, size_t (19));
+
+    in_region1.sized (1000).insert_into (&ly, top_cell.cell_index (), l11);
+    in_region2.sized (1000).insert_into (&ly, top_cell.cell_index (), l12);
+
+    db::compare_layouts (_this, ly, tl::testdata () + "/algo/dss_sparse_array_au1.gds");
+  }
+
+  ly.clear_layer (l11);
+  ly.clear_layer (l12);
+
+  {
+    db::DeepShapeStore dss;
+    dss.set_sparse_array_limit (8.0);
+    EXPECT_EQ (dss.sparse_array_limit (), 8.0);
+
+    db::Region in_region1 (in_it1, dss);
+    db::Region in_region2 (in_it2, dss);
+
+    const db::Layout &dss_ly = dss.layout (0);
+    const db::Cell &dss_top_cell = dss_ly.cell (*dss_ly.begin_top_down ());
+    size_t n_inst = 0;
+    size_t n_total = 0;
+    for (auto i = dss_top_cell.begin (); ! i.at_end (); ++i) {
+      ++n_inst;
+      n_total += i->size ();
+    }
+
+    //  1 array, 1 single inst, 1 3x3 array resolved (=9)
+    EXPECT_EQ (n_inst, size_t (11));
+    EXPECT_EQ (n_total, size_t (19));
+
+    in_region1.sized (1000).insert_into (&ly, top_cell.cell_index (), l11);
+    in_region2.sized (1000).insert_into (&ly, top_cell.cell_index (), l12);
+
+    db::compare_layouts (_this, ly, tl::testdata () + "/algo/dss_sparse_array_au1.gds");
+  }
+
+  ly.clear_layer (l11);
+  ly.clear_layer (l12);
+
+  {
+    db::DeepShapeStore dss;
+    dss.set_sparse_array_limit (1.1);
+
+    db::Region in_region1 (in_it1, dss);
+    db::Region in_region2 (in_it2, dss);
+
+    const db::Layout &dss_ly = dss.layout (0);
+    const db::Cell &dss_top_cell = dss_ly.cell (*dss_ly.begin_top_down ());
+    size_t n_inst = 0;
+    size_t n_total = 0;
+    for (auto i = dss_top_cell.begin (); ! i.at_end (); ++i) {
+      ++n_inst;
+      n_total += i->size ();
+    }
+
+    //  2 3x3 arrays resolved, 1 single inst
+    EXPECT_EQ (n_inst, size_t (19));
+    EXPECT_EQ (n_total, size_t (19));
+
+    in_region1.sized (1000).insert_into (&ly, top_cell.cell_index (), l11);
+    in_region2.sized (1000).insert_into (&ly, top_cell.cell_index (), l12);
+
+    db::compare_layouts (_this, ly, tl::testdata () + "/algo/dss_sparse_array_au1.gds");
+  }
+}
+