Source code for ffcx.analysis

# Copyright (C) 2007-2020 Anders Logg, Martin Alnaes, Kristian B. Oelgaard,
#                         Michal Habera and others
# This file is part of FFCx. (
# SPDX-License-Identifier:    LGPL-3.0-or-later
"""Compiler stage 1: Analysis.

This module implements the analysis/preprocessing of variational forms,
including automatic selection of elements, degrees and form
representation type.

import logging
import typing
from collections import namedtuple

import numpy
import ufl

logger = logging.getLogger("ffcx")

ufl_data = namedtuple('ufl_data', ['form_data', 'unique_elements', 'element_numbers',
                                   'unique_coordinate_elements', 'expressions'])

[docs]def analyze_ufl_objects(ufl_objects: typing.List, parameters: typing.Dict) -> ufl_data: """Analyze ufl object(s). Parameters ---------- ufl_objects parameters FFCx parameters. These parameters take priority over all other set parameters. Returns ------- form_datas Form_data objects unique_elements Unique elements across all forms element_numbers Mapping to unique numbers for all elements unique_coordinate_elements """ * "*")"Compiler stage 1: Analyzing UFL objects") * "*") elements = [] coordinate_elements = [] # Group objects by types forms = [] expressions = [] processed_expressions = [] for ufl_object in ufl_objects: if isinstance(ufl_object, ufl.form.Form): forms += [ufl_object] elif isinstance(ufl_object, ufl.FiniteElementBase): elements += [ufl_object] elif isinstance(ufl_object, ufl.Mesh): coordinate_elements += [ufl_object.ufl_coordinate_element()] elif isinstance(ufl_object[0], ufl.core.expr.Expr): original_expression = ufl_object[0] points = numpy.asarray(ufl_object[1]) expressions += [(original_expression, points)] else: raise TypeError("UFL objects not recognised.") form_data = tuple(_analyze_form(form, parameters) for form in forms) for data in form_data: elements += data.unique_sub_elements coordinate_elements += data.coordinate_elements for original_expression, points in expressions: elements += list(ufl.algorithms.extract_elements(original_expression)) processed_expression = _analyze_expression(original_expression, parameters) processed_expressions += [(processed_expression, points, original_expression)] elements += ufl.algorithms.analysis.extract_sub_elements(elements) # Sort elements so sub-elements come before mixed elements unique_elements = ufl.algorithms.sort_elements(set(elements)) unique_coordinate_element_list = sorted(set(coordinate_elements), key=lambda x: repr(x)) # Compute dict (map) from element to index element_numbers = {element: i for i, element in enumerate(unique_elements)} return ufl_data(form_data=form_data, unique_elements=unique_elements, element_numbers=element_numbers, unique_coordinate_elements=unique_coordinate_element_list, expressions=processed_expressions)
def _analyze_expression(expression: ufl.core.expr.Expr, parameters: typing.Dict): """Analyzes and preprocesses expressions.""" preserve_geometry_types = (ufl.classes.Jacobian, ) expression = ufl.algorithms.apply_algebra_lowering.apply_algebra_lowering(expression) expression = ufl.algorithms.apply_derivatives.apply_derivatives(expression) expression = ufl.algorithms.apply_function_pullbacks.apply_function_pullbacks(expression) expression = ufl.algorithms.apply_geometry_lowering.apply_geometry_lowering(expression, preserve_geometry_types) expression = ufl.algorithms.apply_derivatives.apply_derivatives(expression) expression = ufl.algorithms.apply_geometry_lowering.apply_geometry_lowering(expression, preserve_geometry_types) expression = ufl.algorithms.apply_derivatives.apply_derivatives(expression) complex_mode = "_Complex" in parameters["scalar_type"] if not complex_mode: expression = ufl.algorithms.remove_complex_nodes.remove_complex_nodes(expression) return expression def _analyze_form(form: ufl.form.Form, parameters: typing.Dict) -> ufl.algorithms.formdata.FormData: """Analyzes UFL form and attaches metadata. Parameters ---------- form parameters Returns ------- form_data - Form data computed by UFL with metadata attached Note ---- The main workload of this function is extraction of unique/default metadata from parameters, integral metadata or inherited from UFL (in case of quadrature degree) """ if form.empty(): raise RuntimeError(f"Form ({form}) seems to be zero: cannot compile it.") if _has_custom_integrals(form): raise RuntimeError(f"Form ({form}) contains unsupported custom integrals.") # Set default spacing for coordinate elements to be equispaced for n, i in enumerate(form._integrals): element = i._ufl_domain._ufl_coordinate_element if element._sub_element._variant is None and > 2: sub_element = ufl.FiniteElement(, element.cell(),, element.quadrature_scheme(), variant="equispaced") equi_element = ufl.VectorElement(sub_element) form._integrals[n]._ufl_domain._ufl_coordinate_element = equi_element # Check for complex mode complex_mode = "_Complex" in parameters["scalar_type"] # Compute form metadata form_data = ufl.algorithms.compute_form_data( form, do_apply_function_pullbacks=True, do_apply_integral_scaling=True, do_apply_geometry_lowering=True, preserve_geometry_types=(ufl.classes.Jacobian,), do_apply_restrictions=True, do_append_everywhere_integrals=False, # do not add dx integrals to dx(i) in UFL complex_mode=complex_mode) # Determine unique quadrature degree, quadrature scheme and # precision per each integral data for id, integral_data in enumerate(form_data.integral_data): # Iterate through groups of integral data. There is one integral # data for all integrals with same domain, itype, subdomain_id # (but possibly different metadata). # # Quadrature degree and quadrature scheme must be the same for # all integrals in this integral data group, i.e. must be the # same for for the same (domain, itype, subdomain_id) # Extract precision p_default = -1 precisions = set([integral.metadata().get("precision", p_default) for integral in integral_data.integrals]) precisions.discard(p_default) if len(precisions) == 1: p = precisions.pop() elif len(precisions) == 0: # Default precision p = numpy.finfo("double").precision + 1 # == 16 else: raise RuntimeError("Only one precision allowed within integrals grouped by subdomain.") integral_data.metadata["precision"] = p qd_default = -1 qr_default = "default" for i, integral in enumerate(integral_data.integrals): # Extract quadrature degree qd_metadata = integral.metadata().get("quadrature_degree", qd_default) pd_estimated = numpy.max(integral.metadata()["estimated_polynomial_degree"]) if qd_metadata != qd_default: qd = qd_metadata else: qd = pd_estimated # Extract quadrature rule qr = integral.metadata().get("quadrature_rule", qr_default)"Integral {i}, integral group {id}:")"--- quadrature rule: {qr}")"--- quadrature degree: {qd}")"--- precision: {p}") # Update the old metadata metadata = integral.metadata() metadata.update({"quadrature_degree": qd, "quadrature_rule": qr, "precision": p}) integral_data.integrals[i] = integral.reconstruct(metadata=metadata) return form_data def _has_custom_integrals(o) -> bool: """Check for custom integrals.""" if isinstance(o, ufl.integral.Integral): return o.integral_type() in ufl.custom_integral_types elif isinstance(o, ufl.classes.Form): return any(_has_custom_integrals(itg) for itg in o.integrals()) elif isinstance(o, (list, tuple)): return any(_has_custom_integrals(itg) for itg in o) else: raise NotImplementedError