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Degree 2 Lagrange on a quadrilateral
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- \(R\) is the reference quadrilateral. The following numbering of the subentities of the reference is used:
- \(\mathcal{V}\) is spanned by: \(1\), \(y\), \(y^{2}\), \(x\), \(x y\), \(x y^{2}\), \(x^{2}\), \(x^{2} y\), \(x^{2} y^{2}\)
- \(\mathcal{L}=\{l_0,...,l_{8}\}\)
- Functionals and basis functions:
\(\displaystyle l_{0}:v\mapsto v(0,0)\)
\(\displaystyle \phi_{0} = x y - x - y + 1\)
This DOF is associated with vertex 0 of the reference element.
\(\displaystyle \phi_{0} = x y - x - y + 1\)
This DOF is associated with vertex 0 of the reference element.
\(\displaystyle l_{1}:v\mapsto v(1,0)\)
\(\displaystyle \phi_{1} = x \left(1 - y\right)\)
This DOF is associated with vertex 1 of the reference element.
\(\displaystyle \phi_{1} = x \left(1 - y\right)\)
This DOF is associated with vertex 1 of the reference element.
\(\displaystyle l_{2}:v\mapsto v(0,1)\)
\(\displaystyle \phi_{2} = y \left(1 - x\right)\)
This DOF is associated with vertex 2 of the reference element.
\(\displaystyle \phi_{2} = y \left(1 - x\right)\)
This DOF is associated with vertex 2 of the reference element.
\(\displaystyle l_{3}:v\mapsto v(1,1)\)
\(\displaystyle \phi_{3} = x y\)
This DOF is associated with vertex 3 of the reference element.
\(\displaystyle \phi_{3} = x y\)
This DOF is associated with vertex 3 of the reference element.
\(\displaystyle l_{4}:\mathbf{v}\mapsto\displaystyle\int_{e_{0}}(\sqrt{3} \cdot \left(60 s_{0}^{2} - 60 s_{0} + 10\right))v\)
where \(e_{0}\) is the 0th edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{0}\).
\(\displaystyle \phi_{4} = \sqrt{3} x \left(- x y + x + y - 1\right)\)
This DOF is associated with edge 0 of the reference element.
where \(e_{0}\) is the 0th edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{0}\).
\(\displaystyle \phi_{4} = \sqrt{3} x \left(- x y + x + y - 1\right)\)
This DOF is associated with edge 0 of the reference element.
\(\displaystyle l_{5}:\mathbf{v}\mapsto\displaystyle\int_{e_{1}}(\sqrt{3} \cdot \left(60 s_{0}^{2} - 60 s_{0} + 10\right))v\)
where \(e_{1}\) is the 1st edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{1}\).
\(\displaystyle \phi_{5} = \sqrt{3} y \left(- x y + x + y - 1\right)\)
This DOF is associated with edge 1 of the reference element.
where \(e_{1}\) is the 1st edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{1}\).
\(\displaystyle \phi_{5} = \sqrt{3} y \left(- x y + x + y - 1\right)\)
This DOF is associated with edge 1 of the reference element.
\(\displaystyle l_{6}:\mathbf{v}\mapsto\displaystyle\int_{e_{2}}(\sqrt{3} \cdot \left(60 s_{0}^{2} - 60 s_{0} + 10\right))v\)
where \(e_{2}\) is the 2nd edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{2}\).
\(\displaystyle \phi_{6} = \sqrt{3} x y \left(y - 1\right)\)
This DOF is associated with edge 2 of the reference element.
where \(e_{2}\) is the 2nd edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{2}\).
\(\displaystyle \phi_{6} = \sqrt{3} x y \left(y - 1\right)\)
This DOF is associated with edge 2 of the reference element.
\(\displaystyle l_{7}:\mathbf{v}\mapsto\displaystyle\int_{e_{3}}(\sqrt{3} \cdot \left(60 s_{0}^{2} - 60 s_{0} + 10\right))v\)
where \(e_{3}\) is the 3rd edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{3}\).
\(\displaystyle \phi_{7} = \sqrt{3} x y \left(x - 1\right)\)
This DOF is associated with edge 3 of the reference element.
where \(e_{3}\) is the 3rd edge;
and \(s_{0},s_{1}\) is a parametrisation of \(e_{3}\).
\(\displaystyle \phi_{7} = \sqrt{3} x y \left(x - 1\right)\)
This DOF is associated with edge 3 of the reference element.
\(\displaystyle l_{8}:\mathbf{v}\mapsto\displaystyle\int_{R}(10800 s_{0}^{2} s_{1}^{2} - 10800 s_{0}^{2} s_{1} + 1800 s_{0}^{2} - 10800 s_{0} s_{1}^{2} + 10800 s_{0} s_{1} - 1800 s_{0} + 1800 s_{1}^{2} - 1800 s_{1} + 300)v\)
where \(R\) is the reference element;
and \(s_{0},s_{1}\) is a parametrisation of \(R\).
\(\displaystyle \phi_{8} = 3 x y \left(x y - x - y + 1\right)\)
This DOF is associated with face 0 of the reference element.
where \(R\) is the reference element;
and \(s_{0},s_{1}\) is a parametrisation of \(R\).
\(\displaystyle \phi_{8} = 3 x y \left(x y - x - y + 1\right)\)
This DOF is associated with face 0 of the reference element.