From 4c386b0e45198a12a7869d22d16d32256b6dd66f Mon Sep 17 00:00:00 2001
From: Halvor M Nilsen <Halvor.M.Nilset@ssintef.no>
Date: Fri, 31 Jan 2025 17:27:48 +0100
Subject: [PATCH] Add Preconditions to Avoid Incorrect Interior Sizes

---
 opm/simulators/linalg/ParallelOverlappingILU0_impl.hpp | 5 +++++
 opm/simulators/linalg/PreconditionerFactory_impl.hpp   | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/opm/simulators/linalg/ParallelOverlappingILU0_impl.hpp b/opm/simulators/linalg/ParallelOverlappingILU0_impl.hpp
index 78968b717..822ea19e3 100644
--- a/opm/simulators/linalg/ParallelOverlappingILU0_impl.hpp
+++ b/opm/simulators/linalg/ParallelOverlappingILU0_impl.hpp
@@ -31,6 +31,8 @@
 #include <opm/simulators/linalg/GraphColoring.hpp>
 #include <opm/simulators/linalg/matrixblock.hh>
 
+#include <cassert>
+
 namespace Opm
 {
 namespace detail
@@ -41,6 +43,7 @@ template<class M>
 void ghost_last_bilu0_decomposition (M& A, std::size_t interiorSize)
 {
     // iterator types
+    assert(interiorSize <= A.N());
     using rowiterator = typename M::RowIterator;
     using coliterator = typename M::ColIterator;
     using block = typename M::block_type;
@@ -311,6 +314,7 @@ ParallelOverlappingILU0(const Matrix& A,
 {
     // BlockMatrix is a Subclass of FieldMatrix that just adds
     // methods. Therefore this cast should be safe.
+    assert(interiorSize <= A_->N());
     update( );
 }
 
@@ -443,6 +447,7 @@ update()
 
             if (comm_) {
                 interiorSize_ = detail::set_interiorSize(A_->N(), interiorSize_, *comm_);
+                assert(interiorSize_ <= A_->N());
             }
 
             // create ILU-0 decomposition
diff --git a/opm/simulators/linalg/PreconditionerFactory_impl.hpp b/opm/simulators/linalg/PreconditionerFactory_impl.hpp
index 58e863928..44287b6eb 100644
--- a/opm/simulators/linalg/PreconditionerFactory_impl.hpp
+++ b/opm/simulators/linalg/PreconditionerFactory_impl.hpp
@@ -58,6 +58,8 @@
 #include <opm/simulators/linalg/AmgxPreconditioner.hpp>
 #endif
 
+#include <cassert>
+
 namespace Opm {
 
 template <class Smoother>
@@ -396,6 +398,7 @@ struct StandardPreconditioners {
         // Already a parallel preconditioner. Need to pass comm, but no need to wrap it in a BlockPreconditioner.
         if (ilulevel == 0) {
             const std::size_t num_interior = interiorIfGhostLast(comm);
+            assert(num_interior <= op.getmat().N());
             return std::make_shared<ParallelOverlappingILU0<M, V, V, Comm>>(
                 op.getmat(), comm, w, MILU_VARIANT::ILU, num_interior, redblack, reorder_spheres);
         } else {