Add a 1-point 2D quadrature on [-1,1]*[-1,1]

src/util/fem/Quadrature.cc

@@ -65,6 +65,12 @@ Gaussian2::Gaussian2(double D) {
   m_weights = {0.5 * D, 0.5 * D};
 }
 
+//! One-point quadrature on a rectangle.
+Q1Quadrature1::Q1Quadrature1() {
+  m_points = {{0.0, 0.0, 0.0}};
+  m_weights = {4.0};
+}
+
 //! Two-by-two Gaussian quadrature on a rectangle.
 Q1Quadrature4::Q1Quadrature4() {
 

src/util/fem/Quadrature.hh

@@ -85,6 +85,12 @@ public:
   Gaussian2(double D);
 };
 
+//! The 4-point Gaussian quadrature on the square [-1,1]*[-1,1]
+class Q1Quadrature1 : public Quadrature {
+public:
+  Q1Quadrature1();
+};
+
 //! The 4-point Gaussian quadrature on the square [-1,1]*[-1,1]
 class Q1Quadrature4 : public Quadrature {
 public: