message: fix compile error, changed ComputeGradientBlocked doftrans usage to be similar to MixedBilinearForm::Assemble.
diff: @@ -908,7 +908,10 @@ void BlockNonlinearForm::ComputeGradientBlocked(const BlockVector &bx) const
  for (int l=0; l<fes.Size(); ++l)
  {
  if (elmats(j,l)->Height() == 0) { continue; }
  - if (doftrans[s]) { doftrans[s]->TransformDual(*elmats(j,l)); }
  + if (doftrans[j] || doftrans[l])
  + {
  + TransformDual(doftrans[j], doftrans[l], *elmats(j,l));
  + }
  Grads(j,l)->AddSubMatrix(*vdofs[j], *vdofs[l],
  *elmats(j,l), skip_zeros);
  }
  