From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Sat, 6 Feb 2021 00:25:12 +0000 (-0700)
Subject: Update SparsityPattern/SparseMatrix::copy_from() documentation.
X-Git-Tag: v9.3.0-rc1~483^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F11696%2Fhead;p=dealii.git

Update SparsityPattern/SparseMatrix::copy_from() documentation.
---

diff --git a/include/deal.II/lac/sparse_matrix.h b/include/deal.II/lac/sparse_matrix.h
index d49b7db9ff..2d61224122 100644
--- a/include/deal.II/lac/sparse_matrix.h
+++ b/include/deal.II/lac/sparse_matrix.h
@@ -973,8 +973,12 @@ public:
 
   /**
    * Copy the nonzero entries of a full matrix into this object. Previous
-   * content is deleted. Note that the underlying sparsity pattern must be
-   * appropriate to hold the nonzero entries of the full matrix.
+   * content is deleted.
+   *
+   * Note that the underlying sparsity pattern must be appropriate to
+   * hold the nonzero entries of the full matrix. This can be achieved
+   * using that version of SparsityPattern::copy_from() that takes a
+   * FullMatrix as argument.
    */
   template <typename somenumber>
   void
diff --git a/include/deal.II/lac/sparsity_pattern.h b/include/deal.II/lac/sparsity_pattern.h
index 5d318174ad..e1fe0a6837 100644
--- a/include/deal.II/lac/sparsity_pattern.h
+++ b/include/deal.II/lac/sparsity_pattern.h
@@ -1138,6 +1138,13 @@ public:
    *
    * Previous content of this object is lost, and the sparsity pattern is in
    * compressed mode afterwards.
+   *
+   * Once you have built a sparsity pattern with this function, you
+   * probably want to attach a SparseMatrix object to it. The original
+   * `matrix` object can then be copied into this SparseMatrix object
+   * using the version of SparseMatrix::copy_from() that takes a
+   * FullMatrix object as argument. Through this procedure, you can
+   * convert a FullMatrix into a SparseMatrix.
    */
   template <typename number>
   void