Fix CompositeGridFunctionSpaces with 1 child

These might sound completely silly, but they are useful when writing
code generic w.r.t. the number of components

python/dune/perftool/options.py

@@ -63,7 +63,7 @@ class PerftoolOptionsArray(ImmutableRecord):
     turn_off_diagonal_jacobian = PerftoolOption(default=False, helpstr="Do not use diagonal_jacobian transformation on the ufl tree and cast result of jacobianInverseTransposed into a FieldMatrix.")
     architecture = PerftoolOption(default="haswell", helpstr="The architecture to optimize for. Possible values: haswell|knl")
     grid_offset = PerftoolOption(default=False, helpstr="Set to true if you want a yasp grid where the lower left corner is not in the origin.")
-    simplify = PerftoolOption(default=True, helpstr="Whether to simplify expressions using sympy")
+    simplify = PerftoolOption(default=False, helpstr="Whether to simplify expressions using sympy")
     precision_bits = PerftoolOption(default=64, helpstr="The number of bits for the floating point type")
     assure_statement_ordering = PerftoolOption(default=False, helpstr="Whether special care should be taken for a good statement ordering in sumfact kernels, runs into a loopy scheduler performance bug, but is necessary for production.")
 

python/dune/perftool/pdelab/driver/gridfunctionspace.py

@@ -234,6 +234,8 @@ def name_gfs(element, is_dirichlet, treepath=(), root=True):
             subgfs.append(name_gfs(subel, is_dirichlet[k:k + subel.value_size()], treepath=treepath + (i,), root=False))
             k = k + subel.value_size()
         name = "_".join(subgfs)
+        if len(subgfs) == 1:
+            name = "{}_dummy".format(name)
         name = "{}_{}".format(name, "_".join(str(t) for t in treepath))
         define_composite_gfs(element, is_dirichlet, name, tuple(subgfs), root)
         return name
@@ -272,6 +274,8 @@ def type_gfs(element, is_dirichlet, root=True):
             subgfs.append(type_gfs(subel, is_dirichlet[k:k + subel.value_size()], root=False))
             k = k + subel.value_size()
         name = "_".join(subgfs)
+        if len(subgfs) == 1:
+            name = "{}_dummy".format(name)
         typedef_composite_gfs(element, name, tuple(subgfs), root)
         return name
     else:

python/dune/perftool/pdelab/driver/interpolate.py

@@ -52,6 +52,8 @@ def name_boundary_function(element, func):
             childs.append(name_boundary_function(subel, func[k:k + subel.value_size()]))
             k = k + subel.value_size()
         name = "_".join(childs)
+        if len(childs) == 1:
+            name = "{}_dummy".format(name)
         define_compositegfs_parameterfunction(name, tuple(childs))
         return name
     else: