From 1fab8f77b57598408876998d0d549832add4f40d Mon Sep 17 00:00:00 2001
From: Sven Oesau <sven.oesau@geometryfactory.com>
Date: Thu, 17 Jul 2025 15:32:23 +0200
Subject: [PATCH] bugfix CMakeLists.txt adding log to example/test to indicate
 whether Eigen3 or SuiteSparse is used

---
 .../ARAP_parameterization.cpp                       |  5 +++++
 .../Surface_mesh_parameterization/CMakeLists.txt    |  8 +++++---
 .../Surface_mesh_parameterization/CMakeLists.txt    | 13 +++++++++++++
 .../extensive_parameterization_test.cpp             |  5 +++++
 4 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/ARAP_parameterization.cpp b/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/ARAP_parameterization.cpp
index 6919bd32dc8..192502af616 100644
--- a/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/ARAP_parameterization.cpp
+++ b/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/ARAP_parameterization.cpp
@@ -26,6 +26,11 @@ namespace SMP = CGAL::Surface_mesh_parameterization;
 
 int main(int argc, char** argv)
 {
+#ifdef CGAL_SMP_USE_SUITESPARSE_SOLVERS
+  std::cout << "Using SuiteSparse" << std::endl;
+#else
+  std::cout << "Using Eigen3" << std::endl;
+#endif
   const std::string filename = (argc>1) ? argv[1] : CGAL::data_file_path("meshes/head.off");
 
   SurfaceMesh sm;
diff --git a/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/CMakeLists.txt b/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/CMakeLists.txt
index 59f4bcaec27..d7ad05d47b0 100644
--- a/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/CMakeLists.txt
+++ b/Surface_mesh_parameterization/examples/Surface_mesh_parameterization/CMakeLists.txt
@@ -34,9 +34,11 @@ if(TARGET CGAL::Eigen3_support)
   target_link_libraries(square_border_parameterizer PUBLIC CGAL::Eigen3_support)
   create_single_source_cgal_program( "iterative_authalic_parameterizer.cpp" )
   target_link_libraries(iterative_authalic_parameterizer PUBLIC CGAL::Eigen3_support)
-  if(SuiteSparse_FOUND)
-    target_link_libraries(ARAP_parameterization PRIVATE ${SuiteSparse_LIBRARIES})
-    target_link_libraries(orbifold PRIVATE ${SuiteSparse_LIBRARIES})
+  if(TARGET SuiteSparse::UMFPACK)
+    target_link_libraries(ARAP_parameterization PRIVATE SuiteSparse::UMFPACK)
+    target_link_libraries(orbifold PRIVATE PRIVATE SuiteSparse::UMFPACK)
+    target_compile_definitions(ARAP_parameterization PRIVATE EIGEN_DONT_ALIGN_STATICALLY CGAL_SMP_USE_SUITESPARSE_SOLVERS)
+    target_compile_definitions(orbifold PRIVATE EIGEN_DONT_ALIGN_STATICALLY CGAL_SMP_USE_SUITESPARSE_SOLVERS)
   endif()
 
 else()
diff --git a/Surface_mesh_parameterization/test/Surface_mesh_parameterization/CMakeLists.txt b/Surface_mesh_parameterization/test/Surface_mesh_parameterization/CMakeLists.txt
index 00278df2f7a..885af839aeb 100644
--- a/Surface_mesh_parameterization/test/Surface_mesh_parameterization/CMakeLists.txt
+++ b/Surface_mesh_parameterization/test/Surface_mesh_parameterization/CMakeLists.txt
@@ -6,11 +6,24 @@ project(Surface_mesh_parameterization_Tests)
 # Find CGAL
 find_package(CGAL REQUIRED)
 
+find_package(UMFPACK QUIET NO_MODULE)
+
+if(TARGET SuiteSparse::UMFPACK)
+  message(STATUS "Orbifold Tutte Embeddings will use UmfPackLU")
+else()
+  message(STATUS "NOTICE: Examples will be compiled without the SuiteSparse library and UmfPack. Try setting CMAKE_PREFIX_PATH to your SuiteSparse installation.")
+endif()
+
 find_package(Eigen3 3.1.0 QUIET) #(requires 3.1.0 or greater)
 include(CGAL_Eigen3_support)
 if(TARGET CGAL::Eigen3_support)
   create_single_source_cgal_program("extensive_parameterization_test.cpp")
   target_link_libraries(extensive_parameterization_test PUBLIC CGAL::Eigen3_support)
+
+  if(TARGET SuiteSparse::UMFPACK)
+    target_link_libraries(extensive_parameterization_test PRIVATE SuiteSparse::UMFPACK)
+    target_compile_definitions(extensive_parameterization_test PRIVATE EIGEN_DONT_ALIGN_STATICALLY CGAL_SMP_USE_SUITESPARSE_SOLVERS)
+  endif()
 else()
   message("NOTICE: The tests require Eigen 3.1 (or greater), and will not be compiled.")
 endif()
diff --git a/Surface_mesh_parameterization/test/Surface_mesh_parameterization/extensive_parameterization_test.cpp b/Surface_mesh_parameterization/test/Surface_mesh_parameterization/extensive_parameterization_test.cpp
index ff97d007295..dbfc458d93d 100644
--- a/Surface_mesh_parameterization/test/Surface_mesh_parameterization/extensive_parameterization_test.cpp
+++ b/Surface_mesh_parameterization/test/Surface_mesh_parameterization/extensive_parameterization_test.cpp
@@ -78,6 +78,11 @@ typedef boost::graph_traits<SM_Seam_mesh>::halfedge_descriptor    SM_SE_halfedge
 
 int main(int, char**)
 {
+#ifdef CGAL_SMP_USE_SUITESPARSE_SOLVERS
+  std::cout << "Using SuiteSparse" << std::endl;
+#else
+  std::cout << "Using Eigen3" << std::endl;
+#endif
   std::cout.precision(17);
   CGAL::IO::set_pretty_mode(std::cout);