From: Daniel Arndt <arndtd@ornl.gov>
Date: Wed, 14 Feb 2024 21:31:28 +0000 (-0500)
Subject: Tpetra: Add frobenius_norm to SparseMatrix
X-Git-Tag: relicensing~36^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F16648%2Fhead;p=dealii.git

Tpetra: Add frobenius_norm to SparseMatrix
---

diff --git a/include/deal.II/lac/trilinos_tpetra_sparse_matrix.h b/include/deal.II/lac/trilinos_tpetra_sparse_matrix.h
index 5fbf291cfd..48de7bd615 100644
--- a/include/deal.II/lac/trilinos_tpetra_sparse_matrix.h
+++ b/include/deal.II/lac/trilinos_tpetra_sparse_matrix.h
@@ -706,6 +706,20 @@ namespace LinearAlgebra
                  const Vector<Number, MemorySpace> &src) const;
       /** @} */
 
+      /**
+       * @name Matrix norms
+       */
+      /** @{ */
+
+      /**
+       * Return the frobenius norm of the matrix, i.e. the square root of the
+       * sum of squares of all entries in the matrix.
+       */
+      Number
+      frobenius_norm() const;
+
+      /** @} */
+
       /**
        * @name Mixed Stuff
        */
diff --git a/include/deal.II/lac/trilinos_tpetra_sparse_matrix.templates.h b/include/deal.II/lac/trilinos_tpetra_sparse_matrix.templates.h
index 6dd1acaa63..de1d09db50 100644
--- a/include/deal.II/lac/trilinos_tpetra_sparse_matrix.templates.h
+++ b/include/deal.II/lac/trilinos_tpetra_sparse_matrix.templates.h
@@ -588,6 +588,16 @@ namespace LinearAlgebra
 
 
 
+    template <typename Number, typename MemorySpace>
+    Number
+    SparseMatrix<Number, MemorySpace>::frobenius_norm() const
+    {
+      Assert(matrix->isFillComplete(), ExcMatrixNotCompressed());
+      return matrix->getFrobeniusNorm();
+    }
+
+
+
     template <typename Number, typename MemorySpace>
     void
     SparseMatrix<Number, MemorySpace>::set(const size_type  row,
@@ -919,9 +929,9 @@ namespace LinearAlgebra
                                                const bool      no_error) const
     {
       // Extract local indices in the matrix.
-      const int      trilinos_i = matrix->getRowMap()->getLocalElement(i);
-      const int      trilinos_j = matrix->getColMap()->getLocalElement(j);
-      TrilinosScalar value      = 0.;
+      const int trilinos_i = matrix->getRowMap()->getLocalElement(i);
+      const int trilinos_j = matrix->getColMap()->getLocalElement(j);
+      Number    value      = 0.;
 
       if (trilinos_i == Teuchos::OrdinalTraits<int>::invalid() ||
           trilinos_j == Teuchos::OrdinalTraits<int>::invalid())