Merge pull request #2562 from firedrakeproject/connorjward/assign-wei…

…ghted-sums-only

Only permit scalars and weighted sums for `assign`

firedrake/adjoint/function.py

@@ -149,10 +149,11 @@ def wrapper(self, other, *args, **kwargs):
     def _ad_annotate_iadd(__iadd__):
         @wraps(__iadd__)
         def wrapper(self, other, **kwargs):
+            with stop_annotating():
+                func = __iadd__(self, other, **kwargs)
+
             ad_block_tag = kwargs.pop("ad_block_tag", None)
             annotate = annotate_tape(kwargs)
-            func = __iadd__(self, other, **kwargs)
-
             if annotate:
                 block = FunctionAssignBlock(func, self + other, ad_block_tag=ad_block_tag)
                 tape = get_working_tape()
@@ -167,10 +168,11 @@ def wrapper(self, other, **kwargs):
     def _ad_annotate_isub(__isub__):
         @wraps(__isub__)
         def wrapper(self, other, **kwargs):
+            with stop_annotating():
+                func = __isub__(self, other, **kwargs)
+
             ad_block_tag = kwargs.pop("ad_block_tag", None)
             annotate = annotate_tape(kwargs)
-            func = __isub__(self, other, **kwargs)
-
             if annotate:
                 block = FunctionAssignBlock(func, self - other, ad_block_tag=ad_block_tag)
                 tape = get_working_tape()
@@ -185,10 +187,11 @@ def wrapper(self, other, **kwargs):
     def _ad_annotate_imul(__imul__):
         @wraps(__imul__)
         def wrapper(self, other, **kwargs):
+            with stop_annotating():
+                func = __imul__(self, other, **kwargs)
+
             ad_block_tag = kwargs.pop("ad_block_tag", None)
             annotate = annotate_tape(kwargs)
-            func = __imul__(self, other, **kwargs)
-
             if annotate:
                 block = FunctionAssignBlock(func, self*other, ad_block_tag=ad_block_tag)
                 tape = get_working_tape()
@@ -203,10 +206,11 @@ def wrapper(self, other, **kwargs):
     def _ad_annotate_idiv(__idiv__):
         @wraps(__idiv__)
         def wrapper(self, other, **kwargs):
+            with stop_annotating():
+                func = __idiv__(self, other, **kwargs)
+
             ad_block_tag = kwargs.pop("ad_block_tag", None)
             annotate = annotate_tape(kwargs)
-            func = __idiv__(self, other, **kwargs)
-
             if annotate:
                 block = FunctionAssignBlock(func, self/other, ad_block_tag=ad_block_tag)
                 tape = get_working_tape()

firedrake/assemble.py

@@ -9,10 +9,11 @@
 import finat
 import firedrake
 import numpy
+from pyadjoint.tape import annotate_tape
 from tsfc import kernel_args
 from tsfc.finatinterface import create_element
 import ufl
-from firedrake import (assemble_expressions, extrusion_utils as eutils, matrix, parameters, solving,
+from firedrake import (extrusion_utils as eutils, matrix, parameters, solving,
                        tsfc_interface, utils)
 from firedrake.adjoint import annotate_assemble
 from firedrake.bcs import DirichletBC, EquationBC, EquationBCSplit
@@ -100,7 +101,7 @@ def assemble(expr, *args, **kwargs):
     if isinstance(expr, (ufl.form.Form, slate.TensorBase)):
         return _assemble_form(expr, *args, **kwargs)
     elif isinstance(expr, ufl.core.expr.Expr):
-        return assemble_expressions.assemble_expression(expr)
+        return _assemble_expr(expr)
     else:
         raise TypeError(f"Unable to assemble: {expr}")
 
@@ -290,6 +291,20 @@ def _assemble_form(form, tensor=None, bcs=None, *,
     return assembler.assemble()
 
 
+def _assemble_expr(expr):
+    """Assemble a pointwise expression.
+
+    :arg expr: The :class:`ufl.core.expr.Expr` to be evaluated.
+    :returns: A :class:`firedrake.Function` containing the result of this evaluation.
+    """
+    try:
+        coefficients = ufl.algorithms.extract_coefficients(expr)
+        V, = set(c.function_space() for c in coefficients) - {None}
+    except ValueError:
+        raise ValueError("Cannot deduce correct target space from pointwise expression")
+    return firedrake.Function(V).assign(expr)
+
+
 def _check_inputs(form, tensor, bcs, diagonal):
     # Ensure mesh is 'initialised' as we could have got here without building a
     # function space (e.g. if integrating a constant).
@@ -392,6 +407,12 @@ def assemble(self):
 
         :returns: The assembled object.
         """
+        if annotate_tape():
+            raise NotImplementedError(
+                "Taping with explicit FormAssembler objects is not supported yet. "
+                "Use assemble instead."
+            )
+
         if self._needs_zeroing:
             self._as_pyop2_type(self._tensor).zero()