From 398b4f56ebf93b92f2a170c1eb6fade0591429f0 Mon Sep 17 00:00:00 2001
From: Martin Kronbichler <martin.kronbichler@rub.de>
Date: Fri, 5 Apr 2024 10:30:17 +0200
Subject: [PATCH] Add Quadrature::initialize() function taking ArrayView

---
 include/deal.II/base/quadrature.h | 13 +++++++++++++
 source/base/quadrature.cc         | 25 +++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/include/deal.II/base/quadrature.h b/include/deal.II/base/quadrature.h
index 075ff4218c..8827c895fa 100644
--- a/include/deal.II/base/quadrature.h
+++ b/include/deal.II/base/quadrature.h
@@ -18,6 +18,7 @@
 
 #include <deal.II/base/config.h>
 
+#include <deal.II/base/array_view.h>
 #include <deal.II/base/point.h>
 #include <deal.II/base/subscriptor.h>
 
@@ -243,6 +244,18 @@ public:
   initialize(const std::vector<Point<dim>> &points,
              const std::vector<double>     &weights);
 
+  /**
+   * Set the quadrature points and weights to the values provided in the
+   * arguments. The weights array is allowed to be empty, in which case the
+   * weights are set to infinity. The resulting object is therefore not meant
+   * to actually perform integrations, but rather to be used with FEValues
+   * objects in order to find the position of some points (the quadrature
+   * points in this object) on the transformed cell in real space.
+   */
+  void
+  initialize(const ArrayView<const Point<dim>> &points,
+             const ArrayView<const double>     &weights = {});
+
   /**
    * Number of quadrature points.
    */
diff --git a/source/base/quadrature.cc b/source/base/quadrature.cc
index c1f535198e..376d12c93a 100644
--- a/source/base/quadrature.cc
+++ b/source/base/quadrature.cc
@@ -59,6 +59,31 @@ Quadrature<dim>::initialize(const std::vector<Point<dim>> &p,
 
 
 
+template <int dim>
+void
+Quadrature<dim>::initialize(const ArrayView<const Point<dim>> &points,
+                            const ArrayView<const double>     &weights)
+{
+  this->weights.clear();
+  if (!weights.empty())
+    {
+      AssertDimension(weights.size(), points.size());
+      this->weights.insert(this->weights.end(), weights.begin(), weights.end());
+    }
+  else
+    this->weights.resize(points.size(),
+                         std::numeric_limits<double>::infinity());
+
+  quadrature_points.clear();
+  quadrature_points.insert(quadrature_points.end(),
+                           points.begin(),
+                           points.end());
+
+  is_tensor_product_flag = dim == 1;
+}
+
+
+
 template <int dim>
 Quadrature<dim>::Quadrature(const std::vector<Point<dim>> &points,
                             const std::vector<double>     &weights)
-- 
2.39.5