Only set the gradient norm if we have set up the Riesz map elsewhere

Author: jrmaddison

pyadjoint/optimization/tao_solver.py

@@ -699,9 +699,6 @@ def objective_gradient(tao, x, g):
             hessian_mat.getPythonContext().update,
             H=hessian_mat, P=Pmat or hessian_mat)
 
-        Minv_mat = RieszMapMat(rf.controls, comm=comm)
-        tao.setGradientNorm(Minv_mat)
-
         if problem.bounds is not None:
             lbs = []
             ubs = []
@@ -727,6 +724,9 @@ def objective_gradient(tao, x, g):
         if tao.getType() in {PETSc.TAO.Type.LMVM, PETSc.TAO.Type.BLMVM}:
             n, N = vec_interface.n, vec_interface.N
 
+            Minv_mat = RieszMapMat(rf.controls, comm=comm)
+            tao.setGradientNorm(Minv_mat)
+
             class InitialHessian:
                 """:class:`petsc4py.PETSc.Mat` context.
                 """