Field canonicalization (#661)

* adding hashing for waveforms

* fixing hashing of waveforms.

* adding canonicalization to field with waveform hashing.

* only merging `ScaledLocation` nodes in field canonicalizaiton.

* adding back hash for field object.

* add tests for hash.

* creating new API for `PythonFn` to stop some of the 'hacking' of attributes.

* adding `cached_property` for  `_hash_value`

* simplifying assign.

* adding docstring.

src/bloqade/builder/waveform.py

@@ -1019,7 +1019,7 @@ def sample(
         return Sample(dt, interpolation, self)
 
     def __bloqade_ir__(self):
-        return ir.PythonFn(self._fn, self._duration)
+        return ir.PythonFn.create(self._fn, self._duration)
 
 
 # NOTE: no double-slice or double-record

src/bloqade/codegen/common/assign_variables.py

@@ -91,9 +91,21 @@ def visit_poly(self, ast: waveform.Poly) -> Any:
         return waveform.Poly(checkpoints, duration)
 
     def visit_python_fn(self, ast: waveform.PythonFn) -> Any:
-        new_ast = waveform.PythonFn(ast.fn, self.scalar_visitor.emit(ast.duration))
-        new_ast.parameters = list(map(self.scalar_visitor.emit, ast.parameters))
-        return new_ast
+        duration = self.scalar_visitor.emit(ast.duration)
+        new_parameters = []
+        default_param_values = dict(ast.default_param_values)
+
+        new_parameters = list(map(self.scalar_visitor.emit, ast.parameters))
+
+        # remove default parameters that are overwritten by the assignment
+        for param in new_parameters:
+            if (
+                isinstance(param, scalar.AssignedVariable)
+                and param.name in default_param_values
+            ):
+                default_param_values.pop(param.name)
+
+        return waveform.PythonFn(ast.fn, duration, new_parameters, default_param_values)
 
     def visit_add(self, ast: waveform.Add) -> Any:
         return waveform.Add(self.visit(ast.left), self.visit(ast.right))

src/bloqade/ir/control/field.py

@@ -1,3 +1,4 @@
+from functools import cached_property
 from ..scalar import Scalar, cast
 from ..tree_print import Printer
 from .waveform import Waveform
@@ -107,8 +108,12 @@ class AssignedRunTimeVector(SpatialModulation):
     name: str
     value: List[Decimal]
 
+    @cached_property
+    def _hash_value(self):
+        return hash(self.name) ^ hash(tuple(self.value)) ^ hash(self.__class__)
+
     def __hash__(self) -> int:
-        return hash(self.name) ^ hash(self.__class__) ^ hash(tuple(self.value))
+        return self._hash_value
 
     def print_node(self):
         return "AssgiendRunTimeVector"
@@ -143,9 +148,13 @@ def __init__(self, pairs):
             value[k] = cast(v)
         self.value = value
 
-    def __hash__(self) -> int:
+    @cached_property
+    def _hash_value(self) -> int:
         return hash(frozenset(self.value.items())) ^ hash(self.__class__)
 
+    def __hash__(self) -> int:
+        return self._hash_value
+
     def _get_data(self, **assignments):
         names = []
         scls = []
@@ -197,7 +206,7 @@ def children(self):
         return {"modulation": self.modulation, "waveform": self.waveform}
 
 
-@dataclass
+@dataclass(frozen=True)
 class Field(FieldExpr):
     """Field node in the IR. Which contains collection(s) of
     [`Waveform`][bloqade.ir.control.waveform.Waveform]
@@ -209,9 +218,42 @@ class Field(FieldExpr):
 
     drives: Dict[SpatialModulation, Waveform]
 
-    def __hash__(self) -> int:
+    @cached_property
+    def _hash_value(self):
         return hash(frozenset(self.drives.items())) ^ hash(self.__class__)
 
+    def __hash__(self) -> int:
+        return self._hash_value
+
+    def canonicalize(self) -> "Field":
+        """
+        Canonicalize the Field by merging `ScaledLocation` nodes with the same waveform.
+        """
+        reversed_dirves = {}
+
+        for sm, wf in self.drives.items():
+            reversed_dirves[wf] = reversed_dirves.get(wf, []) + [sm]
+
+        drives = {}
+
+        for wf, sms in reversed_dirves.items():
+            new_sm = [sm for sm in sms if not isinstance(sm, ScaledLocations)]
+            scaled_locations_sm = [sm for sm in sms if isinstance(sm, ScaledLocations)]
+
+            new_mask = {}
+
+            for ele in scaled_locations_sm:
+                for loc, scl in ele.value.items():
+                    new_mask[loc] = new_mask.get(loc, 0) + cast(scl)
+
+            if new_mask:
+                new_sm += [ScaledLocations(new_mask)]
+
+            for sm in new_sm:
+                drives[sm] = wf
+
+        return Field(drives)
+
     def add(self, other):
         if not isinstance(other, Field):
             raise ValueError(f"Cannot add Field and {other.__class__}")
@@ -226,7 +268,7 @@ def add(self, other):
             else:
                 out.drives[spatial_modulation] = waveform
 
-        return out
+        return out.canonicalize()
 
     def print_node(self):
         return "Field"