Use ufl polynomial degree estimation

Note: needs ufl patch

python/dune/perftool/pdelab/quadrature.py

+from ufl.algorithms import estimate_total_polynomial_degree
+
 from dune.perftool import Restriction
 from dune.perftool.generation import (cached,
                                       domain,
+                                      get_global_context_value,
                                       iname,
                                       include_file,
                                       instruction,
@@ -66,11 +69,36 @@ def name_quadrature_weight():
     return name
 
 
+def estimate_quadrature_order():
+    """Estimate quadrature order using polynomial degree estimation from UFL"""
+    # According to UFL documentation estimate_total_polynomial_degree
+    # should only be called on preprocessed forms.
+    form = get_global_context_value("formdata").preprocessed_form
+
+    # Estimate polynomial degree of integrals of current type (eg 'Cell')
+    integral_type = get_global_context_value("integral_type")
+    integrals = form.integrals_by_type(integral_type)
+    polynomial_degree = 0
+    for i in integrals:
+        polynomial_degree = max(polynomial_degree, estimate_total_polynomial_degree(i))
+
+    # Note: In PDELab quadrature order m means that integration of
+    # polynomials of degree m is exact.
+    return polynomial_degree
+
+
 def name_order():
-    # TODO how to determine integration order in a generic fashion here?
-    # Or maybe just read it from the ini file? Or define some mapping from the
-    # finite elements?
-    return "2"
+    # TODO: It should be possible to set the quadrature order as a
+    # user. A global option in the ini file is not really what we want
+    # since it would not be possible to take different quadrature
+    # order for different integral types. Maybe the following would
+    # work:
+    #
+    # - One quadrature order that can be used everywhere
+    # - [formcompiler.quadrature]: Give orders for specific integral
+    #   types.
+    quadrature_order = estimate_quadrature_order()
+    return str(quadrature_order)
 
 
 def quadrature_loop_statement():

python/dune/perftool/sumfact/amatrix.py

@@ -10,6 +10,7 @@ from dune.perftool.generation import (class_member,
 from dune.perftool.pdelab.localoperator import (name_domain_field,
                                                 lop_template_range_field,
                                                 )
+from dune.perftool.pdelab.quadrature import estimate_quadrature_order
 
 
 @class_member("operator")
@@ -29,7 +30,7 @@ def quadrature_points_per_direction():
     # as soon as we have a generic implementation
 
     # Quadrature order
-    q = 2
+    q = estimate_quadrature_order()
 
     # Quadrature points in per direction
     nb_qp = q // 2 + 1