BugFix in gate counts for QROAMClean for small log_block_sizes (#1634)

Author: tanujkhattar

qualtran/bloqs/cryptography/ecc/ec_add_test.py

@@ -443,3 +443,8 @@ def test_ec_add_small(bloq_autotester):
 @pytest.mark.notebook
 def test_notebook():
     qlt_testing.execute_notebook('ec_add')
+
+
+def test_ec_add_small_gate_cost():
+    bloq = _ec_add_small.make()
+    assert get_cost_value(bloq, QECGatesCost()).toffoli == 29

qualtran/bloqs/data_loading/qroam_clean.py

@@ -189,6 +189,8 @@ def build_call_graph(self, ssa: 'SympySymbolAllocator') -> 'BloqCountDictT':
         block_sizes = prod([2**k for k in self.log_block_sizes])
         data_size = prod(self.data_shape)
         n_toffoli = ceil(data_size / block_sizes) + block_sizes - 4 + self.num_controls
+        if not is_symbolic(n_toffoli):
+            n_toffoli = max(0, n_toffoli)
         return {Toffoli(): n_toffoli}
 
     @cached_property
@@ -278,6 +280,8 @@ def build_call_graph(self, ssa: 'SympySymbolAllocator') -> 'BloqCountDictT':
         block_sizes = prod([2**k for k in self.log_block_sizes])
         data_size = prod(self.qroam_clean.data_shape)
         n_toffoli = ceil(data_size / block_sizes) + block_sizes - 4 + self.qroam_clean.num_controls
+        if not is_symbolic(n_toffoli):
+            n_toffoli = max(0, n_toffoli)
         return {Toffoli(): n_toffoli}
 
     def adjoint(self) -> 'QROAMClean':

qualtran/bloqs/data_loading/qroam_clean_test.py

@@ -211,3 +211,19 @@ def test_qroam_clean_classical_sim_multi_dataset():
                 target1_=vals[3],
                 junk_target1_=vals[5],
             ) == (x, y)
+
+
+def test_qroam_clean_small_bloq_counts():
+    qroam_clean = QROAMClean(
+        data_or_shape=(np.array([0, 7]),),
+        selection_bitsizes=(1,),
+        target_bitsizes=(6,),
+        target_shapes=((),),
+        num_controls=0,
+        log_block_sizes=(0,),
+    )
+    assert qroam_clean.t_complexity().t == 0
+    qroam_clean_adj_wrapper = QROAMCleanAdjointWrapper(
+        qroam_clean=qroam_clean, log_block_sizes=(0,)
+    )
+    assert qroam_clean_adj_wrapper.t_complexity().t == 0