# How can i get gauss-lobatto points on a quadrilateral?

How can I get Gauss-Lobatto points on a quadrilateral or a triangle in $x$-$y$ plane?

I am only getting abscissa coordinates and weights by solving Lobatto polynomials using Lobatto quadrature. Please suggest a method to get the $x$-$y$ coordinates

• What do you mean by Gauss-Lobatto points on a triangle? What properties of Gauss-Lobatto do you wish to preserve? – Jesse Chan Nov 18 '15 at 16:10
• the distance between points and number of points i get on sides of a quadrilateral should be same on the sides of a triangle as well... – Nish Dec 14 '15 at 15:27
• i see. if that's the only requirement, you can form the nodes a bunch of different ways. One explicit way is in uea.ac.uk/~h007/publications/lobatto.pdf. Others include Hesthaven and Teng's construction, or Warburton's Warp and Blend nodes. Many of these are described in the Nodal DG Methods book @GoHokies mentioned. – Jesse Chan Dec 15 '15 at 3:55

An example: if your 1D Gauss-Lobatto points are $(x_1,x_2)$, then in 2D you get the following four points: $(x_i,x_j)_{i,j=1,2}$.