Example #1
0
File: fem.py Project: inducer/tsfc
def translate_spatialcoordinate(terminal, mt, ctx):
    # Replace terminal with a Coefficient
    terminal = ctx.coordinate(terminal.ufl_domain())
    # Get back to reference space
    terminal = preprocess_expression(terminal)
    # Rebuild modified terminal
    expr = construct_modified_terminal(mt, terminal)
    # Translate replaced UFL snippet
    return ctx.translator(expr)
Example #2
0
File: fem.py Project: knut0815/tsfc
def translate_spatialcoordinate(terminal, mt, ctx):
    # Replace terminal with a Coefficient
    terminal = ctx.coordinate(terminal.ufl_domain())
    # Get back to reference space
    terminal = preprocess_expression(terminal)
    # Rebuild modified terminal
    expr = construct_modified_terminal(mt, terminal)
    # Translate replaced UFL snippet
    return ctx.translator(expr)
Example #3
0
File: fem.py Project: jmv2009/tsfc
    def preprocess(self, expr, context):
        """Preprocess a UFL expression for translation.

        :arg expr: A UFL expression
        :arg context: The translation context.
        :returns: A new UFL expression
        """
        ifacet = self.interface.integral_type.startswith("interior_facet")
        return preprocess_expression(expr,
                                     complex_mode=context.complex_mode,
                                     do_apply_restrictions=ifacet)
    def to_reference_coordinates(ufl_coordinate_element):
        # Set up UFL form
        cell = ufl_coordinate_element.cell()
        domain = ufl.Mesh(ufl_coordinate_element)
        K = ufl.JacobianInverse(domain)
        x = ufl.SpatialCoordinate(domain)
        x0_element = ufl.VectorElement("Real", cell, 0)
        x0 = ufl.Coefficient(ufl.FunctionSpace(domain, x0_element))
        expr = ufl.dot(K, x - x0)

        # Translation to GEM
        C = ufl_utils.coordinate_coefficient(domain)
        expr = ufl_utils.preprocess_expression(expr)
        expr = ufl_utils.replace_coordinates(expr, C)
        expr = ufl_utils.simplify_abs(expr)

        builder = firedrake_interface.KernelBuilderBase()
        builder._coefficient(C, "C")
        builder._coefficient(x0, "x0")

        dim = cell.topological_dimension()
        point = gem.Variable('X', (dim, ))
        context = tsfc.fem.GemPointContext(
            interface=builder,
            ufl_cell=cell,
            precision=parameters["precision"],
            point_indices=(),
            point_expr=point,
        )
        translator = tsfc.fem.Translator(context)
        ir = map_expr_dag(translator, expr)

        # Unroll result
        ir = [gem.Indexed(ir, alpha) for alpha in numpy.ndindex(ir.shape)]

        # Unroll IndexSums
        max_extent = parameters["unroll_indexsum"]
        if max_extent:

            def predicate(index):
                return index.extent <= max_extent

        ir = gem.optimise.unroll_indexsum(ir, predicate=predicate)

        # Translate to COFFEE
        ir = impero_utils.preprocess_gem(ir)
        return_variable = gem.Variable('dX', (dim, ))
        assignments = [(gem.Indexed(return_variable, (i, )), e)
                       for i, e in enumerate(ir)]
        impero_c = impero_utils.compile_gem(assignments, ())
        body = tsfc.coffee.generate(impero_c, {}, parameters["precision"])
        body.open_scope = False

        return body
Example #5
0
File: fem.py Project: knut0815/tsfc
    def jacobian_at(self, point):
        expr = Jacobian(self.mt.terminal.ufl_domain())
        if self.mt.restriction == '+':
            expr = PositiveRestricted(expr)
        elif self.mt.restriction == '-':
            expr = NegativeRestricted(expr)
        expr = preprocess_expression(expr)

        config = {"point_set": PointSingleton(point)}
        config.update(self.config)
        context = PointSetContext(**config)
        return map_expr_dag(context.translator, expr)
def to_reference_coordinates(ufl_coordinate_element, parameters):
    # Set up UFL form
    cell = ufl_coordinate_element.cell()
    domain = ufl.Mesh(ufl_coordinate_element)
    K = ufl.JacobianInverse(domain)
    x = ufl.SpatialCoordinate(domain)
    x0_element = ufl.VectorElement("Real", cell, 0)
    x0 = ufl.Coefficient(ufl.FunctionSpace(domain, x0_element))
    expr = ufl.dot(K, x - x0)

    # Translation to GEM
    C = ufl.Coefficient(ufl.FunctionSpace(domain, ufl_coordinate_element))
    expr = ufl_utils.preprocess_expression(expr)
    expr = ufl_utils.simplify_abs(expr)

    builder = firedrake_interface.KernelBuilderBase()
    builder.domain_coordinate[domain] = C
    builder._coefficient(C, "C")
    builder._coefficient(x0, "x0")

    dim = cell.topological_dimension()
    point = gem.Variable('X', (dim,))
    context = tsfc.fem.GemPointContext(
        interface=builder,
        ufl_cell=cell,
        precision=parameters["precision"],
        point_indices=(),
        point_expr=point,
    )
    translator = tsfc.fem.Translator(context)
    ir = map_expr_dag(translator, expr)

    # Unroll result
    ir = [gem.Indexed(ir, alpha) for alpha in numpy.ndindex(ir.shape)]

    # Unroll IndexSums
    max_extent = parameters["unroll_indexsum"]
    if max_extent:
        def predicate(index):
            return index.extent <= max_extent
        ir = gem.optimise.unroll_indexsum(ir, predicate=predicate)

    # Translate to COFFEE
    ir = impero_utils.preprocess_gem(ir)
    return_variable = gem.Variable('dX', (dim,))
    assignments = [(gem.Indexed(return_variable, (i,)), e)
                   for i, e in enumerate(ir)]
    impero_c = impero_utils.compile_gem(assignments, ())
    body = tsfc.coffee.generate(impero_c, {}, parameters["precision"])
    body.open_scope = False

    return body
Example #7
0
File: fem.py Project: peide/tsfc
    def physical_edge_lengths(self):
        expr = ufl.classes.CellEdgeVectors(self.mt.terminal.ufl_domain())
        if self.mt.restriction == '+':
            expr = PositiveRestricted(expr)
        elif self.mt.restriction == '-':
            expr = NegativeRestricted(expr)

        expr = ufl.as_vector([ufl.sqrt(ufl.dot(expr[i, :], expr[i, :])) for i in range(3)])
        expr = preprocess_expression(expr)
        config = {"point_set": PointSingleton([1/3, 1/3])}
        config.update(self.config)
        context = PointSetContext(**config)
        return map_expr_dag(context.translator, expr)
Example #8
0
def dg_injection_kernel(Vf, Vc, ncell):
    from firedrake import Tensor, AssembledVector, TestFunction, TrialFunction
    from firedrake.slate.slac import compile_expression
    macro_builder = MacroKernelBuilder(ScalarType_c, ncell)
    f = ufl.Coefficient(Vf)
    macro_builder.set_coefficients([f])
    macro_builder.set_coordinates(Vf.mesh())

    Vfe = create_element(Vf.ufl_element())
    macro_quadrature_rule = make_quadrature(
        Vfe.cell, estimate_total_polynomial_degree(ufl.inner(f, f)))
    index_cache = {}
    parameters = default_parameters()
    integration_dim, entity_ids = lower_integral_type(Vfe.cell, "cell")
    macro_cfg = dict(interface=macro_builder,
                     ufl_cell=Vf.ufl_cell(),
                     precision=parameters["precision"],
                     integration_dim=integration_dim,
                     entity_ids=entity_ids,
                     index_cache=index_cache,
                     quadrature_rule=macro_quadrature_rule)

    fexpr, = fem.compile_ufl(f, **macro_cfg)
    X = ufl.SpatialCoordinate(Vf.mesh())
    C_a, = fem.compile_ufl(X, **macro_cfg)
    detJ = ufl_utils.preprocess_expression(
        abs(ufl.JacobianDeterminant(f.ufl_domain())))
    macro_detJ, = fem.compile_ufl(detJ, **macro_cfg)

    Vce = create_element(Vc.ufl_element())

    coarse_builder = firedrake_interface.KernelBuilder("cell", "otherwise", 0,
                                                       ScalarType_c)
    coarse_builder.set_coordinates(Vc.mesh())
    argument_multiindices = (Vce.get_indices(), )
    argument_multiindex, = argument_multiindices
    return_variable, = coarse_builder.set_arguments((ufl.TestFunction(Vc), ),
                                                    argument_multiindices)

    integration_dim, entity_ids = lower_integral_type(Vce.cell, "cell")
    # Midpoint quadrature for jacobian on coarse cell.
    quadrature_rule = make_quadrature(Vce.cell, 0)

    coarse_cfg = dict(interface=coarse_builder,
                      ufl_cell=Vc.ufl_cell(),
                      precision=parameters["precision"],
                      integration_dim=integration_dim,
                      entity_ids=entity_ids,
                      index_cache=index_cache,
                      quadrature_rule=quadrature_rule)

    X = ufl.SpatialCoordinate(Vc.mesh())
    K = ufl_utils.preprocess_expression(ufl.JacobianInverse(Vc.mesh()))
    C_0, = fem.compile_ufl(X, **coarse_cfg)
    K, = fem.compile_ufl(K, **coarse_cfg)

    i = gem.Index()
    j = gem.Index()

    C_0 = gem.Indexed(C_0, (j, ))
    C_0 = gem.index_sum(C_0, quadrature_rule.point_set.indices)
    C_a = gem.Indexed(C_a, (j, ))
    X_a = gem.Sum(C_0, gem.Product(gem.Literal(-1), C_a))

    K_ij = gem.Indexed(K, (i, j))
    K_ij = gem.index_sum(K_ij, quadrature_rule.point_set.indices)
    X_a = gem.index_sum(gem.Product(K_ij, X_a), (j, ))
    C_0, = quadrature_rule.point_set.points
    C_0 = gem.Indexed(gem.Literal(C_0), (i, ))
    # fine quad points in coarse reference space.
    X_a = gem.Sum(C_0, gem.Product(gem.Literal(-1), X_a))
    X_a = gem.ComponentTensor(X_a, (i, ))

    # Coarse basis function evaluated at fine quadrature points
    phi_c = fem.fiat_to_ufl(
        Vce.point_evaluation(0, X_a, (Vce.cell.get_dimension(), 0)), 0)

    tensor_indices = tuple(gem.Index(extent=d) for d in f.ufl_shape)

    phi_c = gem.Indexed(phi_c, argument_multiindex + tensor_indices)
    fexpr = gem.Indexed(fexpr, tensor_indices)
    quadrature_weight = macro_quadrature_rule.weight_expression
    expr = gem.Product(gem.IndexSum(gem.Product(phi_c, fexpr), tensor_indices),
                       gem.Product(macro_detJ, quadrature_weight))

    quadrature_indices = macro_builder.indices + macro_quadrature_rule.point_set.indices

    reps = spectral.Integrals([expr], quadrature_indices,
                              argument_multiindices, parameters)
    assignments = spectral.flatten([(return_variable, reps)], index_cache)
    return_variables, expressions = zip(*assignments)
    expressions = impero_utils.preprocess_gem(expressions,
                                              **spectral.finalise_options)
    assignments = list(zip(return_variables, expressions))
    impero_c = impero_utils.compile_gem(assignments,
                                        quadrature_indices +
                                        argument_multiindex,
                                        remove_zeros=True)

    index_names = []

    def name_index(index, name):
        index_names.append((index, name))
        if index in index_cache:
            for multiindex, suffix in zip(index_cache[index],
                                          string.ascii_lowercase):
                name_multiindex(multiindex, name + suffix)

    def name_multiindex(multiindex, name):
        if len(multiindex) == 1:
            name_index(multiindex[0], name)
        else:
            for i, index in enumerate(multiindex):
                name_index(index, name + str(i))

    name_multiindex(quadrature_indices, 'ip')
    for multiindex, name in zip(argument_multiindices, ['j', 'k']):
        name_multiindex(multiindex, name)

    index_names.extend(zip(macro_builder.indices, ["entity"]))
    body = generate_coffee(impero_c, index_names, parameters["precision"],
                           ScalarType_c)

    retarg = ast.Decl(ScalarType_c,
                      ast.Symbol("R", rank=(Vce.space_dimension(), )))
    local_tensor = coarse_builder.local_tensor
    local_tensor.init = ast.ArrayInit(
        numpy.zeros(Vce.space_dimension(), dtype=ScalarType_c))
    body.children.insert(0, local_tensor)
    args = [retarg] + macro_builder.kernel_args + [
        macro_builder.coordinates_arg, coarse_builder.coordinates_arg
    ]

    # Now we have the kernel that computes <f, phi_c>dx_c
    # So now we need to hit it with the inverse mass matrix on dx_c

    u = TrialFunction(Vc)
    v = TestFunction(Vc)
    expr = Tensor(ufl.inner(u, v) * ufl.dx).inv * AssembledVector(
        ufl.Coefficient(Vc))
    Ainv, = compile_expression(expr)
    Ainv = Ainv.kinfo.kernel
    A = ast.Symbol(local_tensor.sym.symbol)
    R = ast.Symbol("R")
    body.children.append(
        ast.FunCall(Ainv.name, R, coarse_builder.coordinates_arg.sym, A))
    from coffee.base import Node
    assert isinstance(Ainv._code, Node)
    return op2.Kernel(ast.Node([
        Ainv._code,
        ast.FunDecl("void",
                    "pyop2_kernel_injection_dg",
                    args,
                    body,
                    pred=["static", "inline"])
    ]),
                      name="pyop2_kernel_injection_dg",
                      cpp=True,
                      include_dirs=Ainv._include_dirs,
                      headers=Ainv._headers)
Example #9
0
def compile_expression_at_points(expression, points, coordinates, parameters=None):
    """Compiles a UFL expression to be evaluated at compile-time known
    reference points.  Useful for interpolating UFL expressions onto
    function spaces with only point evaluation nodes.

    :arg expression: UFL expression
    :arg points: reference coordinates of the evaluation points
    :arg coordinates: the coordinate function
    :arg parameters: parameters object
    """
    import coffee.base as ast

    if parameters is None:
        parameters = default_parameters()
    else:
        _ = default_parameters()
        _.update(parameters)
        parameters = _

    # No arguments, please!
    if extract_arguments(expression):
        return ValueError("Cannot interpolate UFL expression with Arguments!")

    # Apply UFL preprocessing
    expression = ufl_utils.preprocess_expression(expression)

    # Initialise kernel builder
    builder = firedrake_interface.ExpressionKernelBuilder()

    # Replace coordinates (if any)
    domain = expression.ufl_domain()
    if domain:
        assert coordinates.ufl_domain() == domain
        builder.domain_coordinate[domain] = coordinates

    # Collect required coefficients
    coefficients = extract_coefficients(expression)
    if has_type(expression, GeometricQuantity):
        coefficients = [coordinates] + coefficients
    builder.set_coefficients(coefficients)

    # Split mixed coefficients
    expression = ufl_utils.split_coefficients(expression, builder.coefficient_split)

    # Translate to GEM
    point_set = PointSet(points)
    config = dict(interface=builder,
                  ufl_cell=coordinates.ufl_domain().ufl_cell(),
                  precision=parameters["precision"],
                  point_set=point_set)
    ir, = fem.compile_ufl(expression, point_sum=False, **config)

    # Deal with non-scalar expressions
    value_shape = ir.shape
    tensor_indices = tuple(gem.Index() for s in value_shape)
    if value_shape:
        ir = gem.Indexed(ir, tensor_indices)

    # Build kernel body
    return_shape = (len(points),) + value_shape
    return_indices = point_set.indices + tensor_indices
    return_var = gem.Variable('A', return_shape)
    return_arg = ast.Decl(SCALAR_TYPE, ast.Symbol('A', rank=return_shape))
    return_expr = gem.Indexed(return_var, return_indices)
    ir, = impero_utils.preprocess_gem([ir])
    impero_c = impero_utils.compile_gem([(return_expr, ir)], return_indices)
    point_index, = point_set.indices
    body = generate_coffee(impero_c, {point_index: 'p'}, parameters["precision"])

    # Handle cell orientations
    if builder.needs_cell_orientations([ir]):
        builder.require_cell_orientations()

    # Build kernel tuple
    return builder.construct_kernel(return_arg, body)
Example #10
0
def compile_expression_at_points(expression,
                                 points,
                                 coordinates,
                                 interface=None,
                                 parameters=None,
                                 coffee=True):
    """Compiles a UFL expression to be evaluated at compile-time known
    reference points.  Useful for interpolating UFL expressions onto
    function spaces with only point evaluation nodes.

    :arg expression: UFL expression
    :arg points: reference coordinates of the evaluation points
    :arg coordinates: the coordinate function
    :arg interface: backend module for the kernel interface
    :arg parameters: parameters object
    :arg coffee: compile coffee kernel instead of loopy kernel
    """
    import coffee.base as ast
    import loopy as lp

    if parameters is None:
        parameters = default_parameters()
    else:
        _ = default_parameters()
        _.update(parameters)
        parameters = _

    # Determine whether in complex mode
    complex_mode = is_complex(parameters["scalar_type"])

    # Apply UFL preprocessing
    expression = ufl_utils.preprocess_expression(expression,
                                                 complex_mode=complex_mode)

    # Initialise kernel builder
    if interface is None:
        if coffee:
            import tsfc.kernel_interface.firedrake as firedrake_interface_coffee
            interface = firedrake_interface_coffee.ExpressionKernelBuilder
        else:
            # Delayed import, loopy is a runtime dependency
            import tsfc.kernel_interface.firedrake_loopy as firedrake_interface_loopy
            interface = firedrake_interface_loopy.ExpressionKernelBuilder

    builder = interface(parameters["scalar_type"])
    arguments = extract_arguments(expression)
    argument_multiindices = tuple(
        builder.create_element(arg.ufl_element()).get_indices()
        for arg in arguments)

    # Replace coordinates (if any)
    domain = expression.ufl_domain()
    if domain:
        assert coordinates.ufl_domain() == domain
        builder.domain_coordinate[domain] = coordinates
        builder.set_cell_sizes(domain)

    # Collect required coefficients
    coefficients = extract_coefficients(expression)
    if has_type(expression, GeometricQuantity) or any(
            fem.needs_coordinate_mapping(c.ufl_element())
            for c in coefficients):
        coefficients = [coordinates] + coefficients
    builder.set_coefficients(coefficients)

    # Split mixed coefficients
    expression = ufl_utils.split_coefficients(expression,
                                              builder.coefficient_split)

    # Translate to GEM
    point_set = PointSet(points)
    config = dict(interface=builder,
                  ufl_cell=coordinates.ufl_domain().ufl_cell(),
                  precision=parameters["precision"],
                  point_set=point_set,
                  argument_multiindices=argument_multiindices)
    ir, = fem.compile_ufl(expression, point_sum=False, **config)

    # Deal with non-scalar expressions
    value_shape = ir.shape
    tensor_indices = tuple(gem.Index() for s in value_shape)
    if value_shape:
        ir = gem.Indexed(ir, tensor_indices)

    # Build kernel body
    return_indices = point_set.indices + tensor_indices + tuple(
        chain(*argument_multiindices))
    return_shape = tuple(i.extent for i in return_indices)
    return_var = gem.Variable('A', return_shape)
    if coffee:
        return_arg = ast.Decl(parameters["scalar_type"],
                              ast.Symbol('A', rank=return_shape))
    else:
        return_arg = lp.GlobalArg("A",
                                  dtype=parameters["scalar_type"],
                                  shape=return_shape)

    return_expr = gem.Indexed(return_var, return_indices)
    ir, = impero_utils.preprocess_gem([ir])
    impero_c = impero_utils.compile_gem([(return_expr, ir)], return_indices)
    point_index, = point_set.indices

    # Handle kernel interface requirements
    builder.register_requirements([ir])
    # Build kernel tuple
    return builder.construct_kernel(return_arg, impero_c,
                                    parameters["precision"],
                                    {point_index: 'p'})
Example #11
0
def dg_injection_kernel(Vf, Vc, ncell):
    from firedrake import Tensor, AssembledVector, TestFunction, TrialFunction
    from firedrake.slate.slac import compile_expression
    macro_builder = MacroKernelBuilder(ncell)
    f = ufl.Coefficient(Vf)
    macro_builder.set_coefficients([f])
    macro_builder.set_coordinates(Vf.mesh())

    Vfe = create_element(Vf.ufl_element())
    macro_quadrature_rule = make_quadrature(Vfe.cell, estimate_total_polynomial_degree(ufl.inner(f, f)))
    index_cache = {}
    parameters = default_parameters()
    integration_dim, entity_ids = lower_integral_type(Vfe.cell, "cell")
    macro_cfg = dict(interface=macro_builder,
                     ufl_cell=Vf.ufl_cell(),
                     precision=parameters["precision"],
                     integration_dim=integration_dim,
                     entity_ids=entity_ids,
                     index_cache=index_cache,
                     quadrature_rule=macro_quadrature_rule)

    fexpr, = fem.compile_ufl(f, **macro_cfg)
    X = ufl.SpatialCoordinate(Vf.mesh())
    C_a, = fem.compile_ufl(X, **macro_cfg)
    detJ = ufl_utils.preprocess_expression(abs(ufl.JacobianDeterminant(f.ufl_domain())))
    macro_detJ, = fem.compile_ufl(detJ, **macro_cfg)

    Vce = create_element(Vc.ufl_element())

    coarse_builder = firedrake_interface.KernelBuilder("cell", "otherwise", 0)
    coarse_builder.set_coordinates(Vc.mesh())
    argument_multiindices = (Vce.get_indices(), )
    argument_multiindex, = argument_multiindices
    return_variable, = coarse_builder.set_arguments((ufl.TestFunction(Vc), ), argument_multiindices)

    integration_dim, entity_ids = lower_integral_type(Vce.cell, "cell")
    # Midpoint quadrature for jacobian on coarse cell.
    quadrature_rule = make_quadrature(Vce.cell, 0)

    coarse_cfg = dict(interface=coarse_builder,
                      ufl_cell=Vc.ufl_cell(),
                      precision=parameters["precision"],
                      integration_dim=integration_dim,
                      entity_ids=entity_ids,
                      index_cache=index_cache,
                      quadrature_rule=quadrature_rule)

    X = ufl.SpatialCoordinate(Vc.mesh())
    K = ufl_utils.preprocess_expression(ufl.JacobianInverse(Vc.mesh()))
    C_0, = fem.compile_ufl(X, **coarse_cfg)
    K, = fem.compile_ufl(K, **coarse_cfg)

    i = gem.Index()
    j = gem.Index()

    C_0 = gem.Indexed(C_0, (j, ))
    C_0 = gem.index_sum(C_0, quadrature_rule.point_set.indices)
    C_a = gem.Indexed(C_a, (j, ))
    X_a = gem.Sum(C_0, gem.Product(gem.Literal(-1), C_a))

    K_ij = gem.Indexed(K, (i, j))
    K_ij = gem.index_sum(K_ij, quadrature_rule.point_set.indices)
    X_a = gem.index_sum(gem.Product(K_ij, X_a), (j, ))
    C_0, = quadrature_rule.point_set.points
    C_0 = gem.Indexed(gem.Literal(C_0), (i, ))
    # fine quad points in coarse reference space.
    X_a = gem.Sum(C_0, gem.Product(gem.Literal(-1), X_a))
    X_a = gem.ComponentTensor(X_a, (i, ))

    # Coarse basis function evaluated at fine quadrature points
    phi_c = fem.fiat_to_ufl(Vce.point_evaluation(0, X_a, (Vce.cell.get_dimension(), 0)), 0)

    tensor_indices = tuple(gem.Index(extent=d) for d in f.ufl_shape)

    phi_c = gem.Indexed(phi_c, argument_multiindex + tensor_indices)
    fexpr = gem.Indexed(fexpr, tensor_indices)
    quadrature_weight = macro_quadrature_rule.weight_expression
    expr = gem.Product(gem.IndexSum(gem.Product(phi_c, fexpr), tensor_indices),
                       gem.Product(macro_detJ, quadrature_weight))

    quadrature_indices = macro_builder.indices + macro_quadrature_rule.point_set.indices

    reps = spectral.Integrals([expr], quadrature_indices, argument_multiindices, parameters)
    assignments = spectral.flatten([(return_variable, reps)], index_cache)
    return_variables, expressions = zip(*assignments)
    expressions = impero_utils.preprocess_gem(expressions, **spectral.finalise_options)
    assignments = list(zip(return_variables, expressions))
    impero_c = impero_utils.compile_gem(assignments, quadrature_indices + argument_multiindex,
                                        remove_zeros=True)

    index_names = []

    def name_index(index, name):
        index_names.append((index, name))
        if index in index_cache:
            for multiindex, suffix in zip(index_cache[index],
                                          string.ascii_lowercase):
                name_multiindex(multiindex, name + suffix)

    def name_multiindex(multiindex, name):
        if len(multiindex) == 1:
            name_index(multiindex[0], name)
        else:
            for i, index in enumerate(multiindex):
                name_index(index, name + str(i))

    name_multiindex(quadrature_indices, 'ip')
    for multiindex, name in zip(argument_multiindices, ['j', 'k']):
        name_multiindex(multiindex, name)

    index_names.extend(zip(macro_builder.indices, ["entity"]))
    body = generate_coffee(impero_c, index_names, parameters["precision"])

    retarg = ast.Decl(SCALAR_TYPE, ast.Symbol("R", rank=(Vce.space_dimension(), )))
    local_tensor = coarse_builder.local_tensor
    local_tensor.init = ast.ArrayInit(numpy.zeros(Vce.space_dimension(), dtype=SCALAR_TYPE))
    body.children.insert(0, local_tensor)
    args = [retarg] + macro_builder.kernel_args + [macro_builder.coordinates_arg,
                                                   coarse_builder.coordinates_arg]

    # Now we have the kernel that computes <f, phi_c>dx_c
    # So now we need to hit it with the inverse mass matrix on dx_c

    u = TrialFunction(Vc)
    v = TestFunction(Vc)
    expr = Tensor(ufl.inner(u, v)*ufl.dx).inv * AssembledVector(ufl.Coefficient(Vc))
    Ainv, = compile_expression(expr)
    Ainv = Ainv.kinfo.kernel
    A = ast.Symbol(local_tensor.sym.symbol)
    R = ast.Symbol("R")
    body.children.append(ast.FunCall(Ainv.name, R, coarse_builder.coordinates_arg.sym, A))
    from coffee.base import Node
    assert isinstance(Ainv._code, Node)
    return op2.Kernel(ast.Node([Ainv._code,
                                ast.FunDecl("void", "pyop2_kernel_injection_dg", args, body,
                                            pred=["static", "inline"])]),
                      name="pyop2_kernel_injection_dg",
                      cpp=True,
                      include_dirs=Ainv._include_dirs,
                      headers=Ainv._headers)
Example #12
0
def compile_expression_dual_evaluation(expression,
                                       to_element,
                                       *,
                                       domain=None,
                                       interface=None,
                                       parameters=None,
                                       coffee=False):
    """Compile a UFL expression to be evaluated against a compile-time known reference element's dual basis.

    Useful for interpolating UFL expressions into e.g. N1curl spaces.

    :arg expression: UFL expression
    :arg to_element: A FInAT element for the target space
    :arg domain: optional UFL domain the expression is defined on (required when expression contains no domain).
    :arg interface: backend module for the kernel interface
    :arg parameters: parameters object
    :arg coffee: compile coffee kernel instead of loopy kernel
    """
    import coffee.base as ast
    import loopy as lp

    # Just convert FInAT element to FIAT for now.
    # Dual evaluation in FInAT will bring a thorough revision.
    to_element = to_element.fiat_equivalent

    if any(len(dual.deriv_dict) != 0 for dual in to_element.dual_basis()):
        raise NotImplementedError(
            "Can only interpolate onto dual basis functionals without derivative evaluation, sorry!"
        )

    if parameters is None:
        parameters = default_parameters()
    else:
        _ = default_parameters()
        _.update(parameters)
        parameters = _

    # Determine whether in complex mode
    complex_mode = is_complex(parameters["scalar_type"])

    # Find out which mapping to apply
    try:
        mapping, = set(to_element.mapping())
    except ValueError:
        raise NotImplementedError(
            "Don't know how to interpolate onto zany spaces, sorry")
    expression = apply_mapping(expression, mapping, domain)

    # Apply UFL preprocessing
    expression = ufl_utils.preprocess_expression(expression,
                                                 complex_mode=complex_mode)

    # Initialise kernel builder
    if interface is None:
        if coffee:
            import tsfc.kernel_interface.firedrake as firedrake_interface_coffee
            interface = firedrake_interface_coffee.ExpressionKernelBuilder
        else:
            # Delayed import, loopy is a runtime dependency
            import tsfc.kernel_interface.firedrake_loopy as firedrake_interface_loopy
            interface = firedrake_interface_loopy.ExpressionKernelBuilder

    builder = interface(parameters["scalar_type"])
    arguments = extract_arguments(expression)
    argument_multiindices = tuple(
        builder.create_element(arg.ufl_element()).get_indices()
        for arg in arguments)

    # Replace coordinates (if any) unless otherwise specified by kwarg
    if domain is None:
        domain = expression.ufl_domain()
    assert domain is not None

    # Collect required coefficients
    first_coefficient_fake_coords = False
    coefficients = extract_coefficients(expression)
    if has_type(expression, GeometricQuantity) or any(
            fem.needs_coordinate_mapping(c.ufl_element())
            for c in coefficients):
        # Create a fake coordinate coefficient for a domain.
        coords_coefficient = ufl.Coefficient(
            ufl.FunctionSpace(domain, domain.ufl_coordinate_element()))
        builder.domain_coordinate[domain] = coords_coefficient
        builder.set_cell_sizes(domain)
        coefficients = [coords_coefficient] + coefficients
        first_coefficient_fake_coords = True
    builder.set_coefficients(coefficients)

    # Split mixed coefficients
    expression = ufl_utils.split_coefficients(expression,
                                              builder.coefficient_split)

    # Translate to GEM
    kernel_cfg = dict(
        interface=builder,
        ufl_cell=domain.ufl_cell(),
        # FIXME: change if we ever implement
        # interpolation on facets.
        integral_type="cell",
        argument_multiindices=argument_multiindices,
        index_cache={},
        scalar_type=parameters["scalar_type"])

    if all(
            isinstance(dual, PointEvaluation)
            for dual in to_element.dual_basis()):
        # This is an optimisation for point-evaluation nodes which
        # should go away once FInAT offers the interface properly
        qpoints = []
        # Everything is just a point evaluation.
        for dual in to_element.dual_basis():
            ptdict = dual.get_point_dict()
            qpoint, = ptdict.keys()
            (qweight, component), = ptdict[qpoint]
            assert allclose(qweight, 1.0)
            assert component == ()
            qpoints.append(qpoint)
        point_set = PointSet(qpoints)
        config = kernel_cfg.copy()
        config.update(point_set=point_set)

        # Allow interpolation onto QuadratureElements to refer to the quadrature
        # rule they represent
        if isinstance(to_element, FIAT.QuadratureElement):
            assert allclose(asarray(qpoints), asarray(to_element._points))
            quad_rule = QuadratureRule(point_set, to_element._weights)
            config["quadrature_rule"] = quad_rule

        expr, = fem.compile_ufl(expression, **config, point_sum=False)
        # In some cases point_set.indices may be dropped from expr, but nothing
        # new should now appear
        assert set(expr.free_indices) <= set(
            chain(point_set.indices, *argument_multiindices))
        shape_indices = tuple(gem.Index() for _ in expr.shape)
        basis_indices = point_set.indices
        ir = gem.Indexed(expr, shape_indices)
    else:
        # This is general code but is more unrolled than necssary.
        dual_expressions = []  # one for each functional
        broadcast_shape = len(expression.ufl_shape) - len(
            to_element.value_shape())
        shape_indices = tuple(gem.Index()
                              for _ in expression.ufl_shape[:broadcast_shape])
        expr_cache = {}  # Sharing of evaluation of the expression at points
        for dual in to_element.dual_basis():
            pts = tuple(sorted(dual.get_point_dict().keys()))
            try:
                expr, point_set = expr_cache[pts]
            except KeyError:
                point_set = PointSet(pts)
                config = kernel_cfg.copy()
                config.update(point_set=point_set)
                expr, = fem.compile_ufl(expression, **config, point_sum=False)
                # In some cases point_set.indices may be dropped from expr, but
                # nothing new should now appear
                assert set(expr.free_indices) <= set(
                    chain(point_set.indices, *argument_multiindices))
                expr = gem.partial_indexed(expr, shape_indices)
                expr_cache[pts] = expr, point_set
            weights = collections.defaultdict(list)
            for p in pts:
                for (w, cmp) in dual.get_point_dict()[p]:
                    weights[cmp].append(w)
            qexprs = gem.Zero()
            for cmp in sorted(weights):
                qweights = gem.Literal(weights[cmp])
                qexpr = gem.Indexed(expr, cmp)
                qexpr = gem.index_sum(
                    gem.Indexed(qweights, point_set.indices) * qexpr,
                    point_set.indices)
                qexprs = gem.Sum(qexprs, qexpr)
            assert qexprs.shape == ()
            assert set(qexprs.free_indices) == set(
                chain(shape_indices, *argument_multiindices))
            dual_expressions.append(qexprs)
        basis_indices = (gem.Index(), )
        ir = gem.Indexed(gem.ListTensor(dual_expressions), basis_indices)

    # Build kernel body
    return_indices = basis_indices + shape_indices + tuple(
        chain(*argument_multiindices))
    return_shape = tuple(i.extent for i in return_indices)
    return_var = gem.Variable('A', return_shape)
    if coffee:
        return_arg = ast.Decl(parameters["scalar_type"],
                              ast.Symbol('A', rank=return_shape))
    else:
        return_arg = lp.GlobalArg("A",
                                  dtype=parameters["scalar_type"],
                                  shape=return_shape)

    return_expr = gem.Indexed(return_var, return_indices)

    # TODO: one should apply some GEM optimisations as in assembly,
    # but we don't for now.
    ir, = impero_utils.preprocess_gem([ir])
    impero_c = impero_utils.compile_gem([(return_expr, ir)], return_indices)
    index_names = dict(
        (idx, "p%d" % i) for (i, idx) in enumerate(basis_indices))
    # Handle kernel interface requirements
    builder.register_requirements([ir])
    # Build kernel tuple
    return builder.construct_kernel(return_arg, impero_c, index_names,
                                    first_coefficient_fake_coords)