Compute the area of each triangle within the triangulation of points.

        Returns
        -------
         area : array of floats, shape (nt,)
            area of each triangle in self.simplices where nt
            is the number of triangles.

def areas(self):
        """
        Compute the area of each triangle within the triangulation of points.

        Returns
        -------
         area : array of floats, shape (nt,)
            area of each triangle in self.simplices where nt
            is the number of triangles.

        """
        v1 = self.points[self.simplices[:,1]] - self.points[self.simplices[:,0]]
        v2 = self.points[self.simplices[:,2]] - self.points[self.simplices[:,1]]

        area = 0.5*(v1[:,0]*v2[:,1] - v1[:,1]*v2[:,0])
        return area