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Description
Describe the bug
We are able to assign individual components of a vector function u extracted as u.sub(i), but interpolate fails on individual components.
Steps to Reproduce
Steps to reproduce the behavior:
from firedrake import *
mesh = UnitSquareMesh(1, 1)
x = mesh.coordinates
V = x.function_space()
u = Function(V)
u.sub(0).assign(x.sub(0)) # works
u.sub(0).interpolate(x.sub(0)) # fails
Expected behavior
Interpolation of indexed components should be supported.
Error message
File petsc4py/PETSc/Log.pyx:188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func()
File petsc4py/PETSc/Log.pyx:189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func()
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/function.py:413, in Function.interpolate(self, expression, subset, allow_missing_dofs, default_missing_val, ad_block_tag)
408 V = self.function_space()
409 interp = interpolation.Interpolate(expression, V,
410 subset=subset,
411 allow_missing_dofs=allow_missing_dofs,
412 default_missing_val=default_missing_val)
--> 413 return assemble(interp, tensor=self, ad_block_tag=ad_block_tag)
File petsc4py/PETSc/Log.pyx:188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func()
File petsc4py/PETSc/Log.pyx:189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func()
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/adjoint_utils/assembly.py:30, in annotate_assemble.<locals>.wrapper(form, *args, **kwargs)
28 form = BaseFormAssembler.preprocess_base_form(form)
29 kwargs['is_base_form_preprocessed'] = True
---> 30 output = assemble(form, *args, **kwargs)
32 from firedrake.function import Function
33 from firedrake.cofunction import Cofunction
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/assemble.py:133, in assemble(expr, *args, **kwargs)
131 raise RuntimeError(f"Got unexpected args: {args}")
132 tensor = kwargs.pop("tensor", None)
--> 133 return get_assembler(expr, *args, **kwargs).assemble(tensor=tensor)
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/assemble.py:381, in BaseFormAssembler.assemble(self, tensor)
379 # DAG assembly: traverse the DAG in a post-order fashion and evaluate the node on the fly.
380 visited = {}
--> 381 result = BaseFormAssembler.base_form_postorder_traversal(self._form, visitor, visited)
383 if tensor:
384 BaseFormAssembler.update_tensor(result, tensor)
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/assemble.py:603, in BaseFormAssembler.base_form_postorder_traversal(expr, visitor, visited)
601 stack.extend(unvisited_children)
602 else:
--> 603 visited[e] = visitor(e, *(visited[arg] for arg in operands))
605 return visited[expr]
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/assemble.py:377, in BaseFormAssembler.assemble.<locals>.visitor(e, *operands)
375 def visitor(e, *operands):
376 t = tensor if e is self._form else None
--> 377 return self.base_form_assembly_visitor(e, t, *operands)
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/assemble.py:550, in BaseFormAssembler.base_form_assembly_visitor(self, expr, tensor, *args)
548 if tensor is None:
549 return interpolator._interpolate(default_missing_val=default_missing_val)
--> 550 return firedrake.Interpolator(expression, tensor, **interp_data)._interpolate(default_missing_val=default_missing_val)
551 elif rank == 2:
552 res = tensor.petscmat if tensor else PETSc.Mat()
File /scratch/brubeckmarti/firedrake/src/pyadjoint/pyadjoint/tape.py:110, in no_annotations.<locals>.wrapper(*args, **kwargs)
107 @wraps(function)
108 def wrapper(*args, **kwargs):
109 with stop_annotating():
--> 110 return function(*args, **kwargs)
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/interpolation.py:818, in SameMeshInterpolator.__init__(self, expr, V, subset, freeze_expr, access, bcs, **kwargs)
816 super().__init__(expr, V, subset, freeze_expr, access, bcs)
817 try:
--> 818 self.callable, arguments = make_interpolator(expr, V, subset, access, bcs=bcs)
819 except FIAT.hdiv_trace.TraceError:
820 raise NotImplementedError("Can't interpolate onto traces sorry")
File petsc4py/PETSc/Log.pyx:188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func()
File petsc4py/PETSc/Log.pyx:189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func()
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/interpolation.py:999, in make_interpolator(expr, V, subset, access, bcs)
996 if len(V) > 1:
997 raise NotImplementedError(
998 "UFL expressions for mixed functions are not yet supported.")
--> 999 loops.extend(_interpolator(V, tensor, expr, subset, arguments, access, bcs=bcs))
1000 if bcs and len(arguments) == 0:
1001 loops.extend([partial(bc.apply, f) for bc in bcs])
File <decorator-gen-49>:2, in _interpolator(V, tensor, expr, subset, arguments, access, bcs)
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/utils.py:89, in known_pyop2_safe.<locals>.wrapper(f, *args, **kwargs)
87 opts["type_check"] = safe
88 try:
---> 89 return f(*args, **kwargs)
90 finally:
91 opts["type_check"] = check
File /scratch/brubeckmarti/firedrake/src/firedrake/firedrake/interpolation.py:1130, in _interpolator(V, tensor, expr, subset, arguments, access, bcs)
1128 assert access == op2.WRITE # Other access descriptors not done for Matrices.
1129 rows_map = V.cell_node_map()
-> 1130 Vcol = arguments[0].function_space()
1131 if isinstance(target_mesh.topology, firedrake.mesh.VertexOnlyMeshTopology):
1132 columns_map = Vcol.cell_node_map()
IndexError: list index out of range