From e8515f78ac098329ab9f8cab21c87caede090a3f Mon Sep 17 00:00:00 2001
From: Charles Schlosser <cs.schlosser@gmail.com>
Date: Thu, 5 Oct 2023 17:13:37 +0000
Subject: [PATCH] Fix sparse triangular view iterator

---
 Eigen/src/SparseCore/SparseTriangularView.h | 4 ++--
 test/sparse_basic.cpp                       | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/Eigen/src/SparseCore/SparseTriangularView.h b/Eigen/src/SparseCore/SparseTriangularView.h
index 5cac8251d..2e53114c2 100644
--- a/Eigen/src/SparseCore/SparseTriangularView.h
+++ b/Eigen/src/SparseCore/SparseTriangularView.h
@@ -152,8 +152,8 @@ public:
         }
       }
 
-//       inline Index row() const { return (ArgType::Flags&RowMajorBit ? Base::outer() : this->index()); }
-//       inline Index col() const { return (ArgType::Flags&RowMajorBit ? this->index() : Base::outer()); }
+      inline Index row() const { return (ArgType::Flags&RowMajorBit ? Base::outer() : this->index()); }
+      inline Index col() const { return (ArgType::Flags&RowMajorBit ? this->index() : Base::outer()); }
       inline StorageIndex index() const
       {
         if(HasUnitDiag && m_returnOne)  return internal::convert_index<StorageIndex>(Base::outer());
diff --git a/test/sparse_basic.cpp b/test/sparse_basic.cpp
index 9e102b742..298619e69 100644
--- a/test/sparse_basic.cpp
+++ b/test/sparse_basic.cpp
@@ -746,6 +746,11 @@ template<typename SparseMatrixType> void sparse_basic(const SparseMatrixType& re
     // check sparse-triangular to dense
     refMat3 = m2.template triangularView<StrictlyUpper>();
     VERIFY_IS_APPROX(refMat3, DenseMatrix(refMat2.template triangularView<StrictlyUpper>()));
+
+    // check sparse triangular view iteration-based evaluation
+    m2.setZero();
+    VERIFY_IS_CWISE_EQUAL(m2.template triangularView<UnitLower>().toDense(), DenseMatrix::Identity(rows, cols));
+    VERIFY_IS_CWISE_EQUAL(m2.template triangularView<UnitUpper>().toDense(), DenseMatrix::Identity(rows, cols));
   }
   
   // test selfadjointView