fix quadrature scaling

src/operator.jl

@@ -35,7 +35,7 @@ a(op::Poisson, xloc, u, du, v, dv) = dot(du, dv)
 # degree 2 quadrature on triangle
 quadrature() = SA[1/6, 1/6, 1/6], SA[1/6 4/6 1/6; 1/6 1/6 4/6]
 # degree 1 quadrature on triangle using corner points
-quadrature_lumped() = SA[1/3, 1/3, 1/3], SA[0. 0. 1.; 0. 1. 0.]
+quadrature_lumped() = SA[1/6, 1/6, 1/6], SA[0. 0. 1.; 0. 1. 0.]
 
 
 assemble(op::Operator) = assemble(op.space,