On 21/05/18 14:50, Matthew Knepley wrote:
> This should do the 1-norm and the \infty-norm

errornorm (and norm, which it uses) compute the L^2 (H1, H(div),
H(curl)) norms.  Adding the p-norm:

||f||_p = (\int |f|^p dx)^(1/p)

is easy to do.

The inf-norm is harder, because the the function is not contained in
the hull defined by its piecewise linear interpolant at the nodes.

Or do you want (not currently implemented, but available via the Vec
representation) the discrete l2/l1/linf norms?  Available as:

with assemble(expr).dat.vec_ro as v:
   v.norm(whatever norm type)

Lawrence