Fix coefficient type for GlobalPhase, and convert from cirq correctly (#901)

* Fix coefficient type `GlobalPhase`, and convert from cirq correctly

* add `sconj` to symbolic utils

Author: anurudhp

qualtran/bloqs/basic_gates/global_phase.py

@@ -24,6 +24,7 @@
 
 if TYPE_CHECKING:
     from qualtran import CompositeBloq
+    from qualtran.resource_counting.symbolic_counting_utils import SymbolicComplex
 
 
 @frozen
@@ -35,7 +36,7 @@ class GlobalPhase(CirqGateAsBloqBase):
         eps: precision
     """
 
-    coefficient: complex
+    coefficient: 'SymbolicComplex'
     eps: float = 1e-11
 
     @property
@@ -46,7 +47,9 @@ def decompose_bloq(self) -> 'CompositeBloq':
         raise DecomposeTypeError(f"{self} is atomic")
 
     def adjoint(self) -> 'GlobalPhase':
-        return attrs.evolve(self, coefficient=complex(self.coefficient).conjugate())
+        from qualtran.resource_counting.symbolic_counting_utils import sconj
+
+        return attrs.evolve(self, coefficient=sconj(self.coefficient))
 
     def pretty_name(self) -> str:
         return 'GPhase'

qualtran/cirq_interop/_cirq_to_bloq.py

@@ -399,7 +399,7 @@ def _cirq_gate_to_bloq(gate: cirq.Gate) -> Bloq:
             exponent=gate.exponent, global_shift=gate.global_shift
         )
 
-    if isinstance(gate, cirq.GlobalPhaseGate) and isinstance(gate.coefficient, (float, complex)):
+    if isinstance(gate, cirq.GlobalPhaseGate):
         return GlobalPhase(coefficient=gate.coefficient)
 
     # No known basic gate, wrap the cirq gate in a CirqGateAsBloq wrapper.

qualtran/resource_counting/symbolic_counting_utils.py

@@ -24,6 +24,9 @@
 SymbolicInt = Union[int, sympy.Expr]
 document(SymbolicFloat, """A floating point value or a sympy expression.""")
 
+SymbolicComplex = Union[complex, sympy.Expr]
+document(SymbolicComplex, """A complex value or a sympy expression.""")
+
 
 @frozen
 class Shaped:
@@ -118,6 +121,11 @@ def acos(x: SymbolicFloat) -> SymbolicFloat:
     return sympy.acos(x)
 
 
+def sconj(x: SymbolicComplex) -> SymbolicComplex:
+    """Compute the complex conjugate."""
+    return sympy.conjugate(x) if is_symbolic(x) else np.conjugate(x)
+
+
 def slen(x: Union[Sized, Shaped]) -> SymbolicInt:
     if isinstance(x, Shaped):
         return x.shape[0]