Fig. 10

Convergence in \(|||\cdot |||_h\) norm and condition numbers for the manufactured problem using basis removal with \(C^1Q^2\)-spline basis. The tolerances used in the selection procedure is \(tol = c h^p \times \sqrt{E}\) and we note that the choices \(c=10^{-1}\) and \(c=10^{-2}\) give no visible difference in the error compared to using the full approximation space (\(c=0\)). a Energy norm convergence. b Condition number