Fix #1782 and #1783: LinearCombinaison adjoint is more general and checks are correct (#1784)

This implements solutions to #1783 and #1782, ~~still need to implement
some tests~~.

Author: petim0

qualtran/bloqs/block_encoding/linear_combination.py

@@ -108,10 +108,15 @@ def __attrs_post_init__(self):
                 "If given, prepare and select oracles must have same selection registers."
             )
         if self._select is not None and self._select.target_registers != (
-            self.signature.get_left("system"),
+            Register(
+                "system",
+                QAny(self.system_bitsize + self.be_ancilla_bitsize + self.be_resource_bitsize),
+            ),
         ):
             raise ValueError(
-                "If given, select oracle must have block encoding `system` register as target."
+                "Invalid select oracle target registers. "
+                "The `system` register must include the block encoding's system, ancilla, "
+                "and resource registers."
             )
         if not all(
             isinstance(u.signal_state.prepare, PrepareIdentity) for u in self._block_encodings
@@ -367,8 +372,13 @@ def get_ctrl_system(self, ctrl_spec: 'CtrlSpec') -> tuple['Bloq', 'AddControlled
             ctrl_reg_name='ctrl',
         )
 
-    def adjoint(self) -> 'LinearCombination':
-        return self
+    def adjoint(self) -> 'Bloq':
+        from qualtran.bloqs.mcmt.specialized_ctrl import (
+            AdjointWithSpecializedCtrl,
+            SpecializeOnCtrlBit,
+        )
+
+        return AdjointWithSpecializedCtrl(self, SpecializeOnCtrlBit.ONE)
 
 
 @bloq_example

qualtran/bloqs/block_encoding/linear_combination_test.py

@@ -164,6 +164,23 @@ def test_linear_combination5(lambd):
     run_gate_test([TGate(), Hadamard(), XGate(), ZGate(), Ry(angle=np.pi / 4.0)], lambd)
 
 
+@pytest.mark.parametrize('lambd', exact3)
+def test_linear_combinaison_hermician_when_bloqs_hermician(lambd):
+    gates = [Hadamard().controlled(), CNOT(), Swap(1)]
+    bloq = LinearCombination(tuple(Unitary(g) for g in gates), lambd, lambd_bits=1)
+    np.testing.assert_allclose(bloq.tensor_contract(), bloq.adjoint().tensor_contract(), atol=1e-16)
+
+
+@pytest.mark.parametrize('lambd', exact3)
+def test_linear_combinaison_not_hermician_when_bloqs_not_hermician(lambd):
+    gates = [TGate().controlled(), CNOT(), Swap(1)]
+    bloq = LinearCombination(tuple(Unitary(g) for g in gates), lambd, lambd_bits=1)
+    with pytest.raises(AssertionError):
+        np.testing.assert_allclose(
+            bloq.tensor_contract(), bloq.adjoint().tensor_contract(), atol=1e-16
+        )
+
+
 # coefficients are not multiples of small negative powers of 2 after normalization
 approx2 = [
     [1 / 3, 2 / 3],

qualtran/bloqs/multiplexers/apply_lth_bloq.py

@@ -127,6 +127,14 @@ def get_ctrl_system(self, ctrl_spec: 'CtrlSpec') -> Tuple['Bloq', 'AddControlled
             get_ctrl_bloq_and_ctrl_reg_name=lambda cv: (evolve(self, control_val=cv), 'control'),
         )
 
+    def adjoint(self) -> 'Bloq':
+        from qualtran.bloqs.mcmt.specialized_ctrl import (
+            AdjointWithSpecializedCtrl,
+            SpecializeOnCtrlBit,
+        )
+
+        return AdjointWithSpecializedCtrl(self, SpecializeOnCtrlBit.BOTH)
+
 
 @bloq_example
 def _apply_lth_bloq() -> ApplyLthBloq: