fix for bug #470

Signed-off-by: Alex McCaskey <mccaskeyaj@ornl.gov>

README.md

@@ -30,7 +30,7 @@ $ build/quantum/examples/qasm/deuteron_from_qasm
 $ python3 python/examples/deuteronH2.py
 
 [run some XACC benchmarks]
-$ python3 -m xacc --benchmark python/benchmark/chemistry/benchmarks/tnqvm_nah_ucc1.ini 
+$ python3 -m xacc --benchmark python/benchmark/chemistry/benchmarks/nah_ucc1.ini 
 ```
 All code is here and you can quickly start developing. We recommend 
 turning on file auto-save by clicking ``File > Auto Save ``.

python/benchmark/chemistry/benchmarks/nah_ucc1.ini

+[XACC]
+accelerator = qpp
+
+[Benchmark]
+name = chemistry
+algorithm = vqe
+
+[Ansatz]
+source = .compiler xasm
+    .circuit ansatz2
+    .parameters x
+    .qbit q
+    X(q[0]);
+    X(q[2]);
+    ucc1(q, x);
+
+[Observable]
+name = pyscf
+basis = sto-3g
+geometry = Na  0.000000   0.0      0.0
+       H   0.0        0.0  1.914388
+fo = [0, 1, 2, 3, 4, 10, 11, 12, 13, 14]
+ao = [5, 9, 15, 19]
+
+[Optimizer]
+name = nlopt
\ No newline at end of file

python/benchmark/chemistry/benchmarks/tnqvm_nah_ucc1.ini

@@ -12,15 +12,13 @@ source = .compiler xasm
     .qbit q
     X(q[0]);
     X(q[2]);
-    ucc1(q, x[0]);
+    ucc1(q, x);
 
 [Observable]
-name = psi4
+name = pyscf
 basis = sto-3g
-geometry = 0 1
-       Na  0.000000   0.0      0.0
+geometry = Na  0.000000   0.0      0.0
        H   0.0        0.0  1.914388
-       symmetry c1
 fo = [0, 1, 2, 3, 4, 10, 11, 12, 13, 14]
 ao = [5, 9, 15, 19]
 

python/xacc.py

@@ -34,7 +34,6 @@ try:
 except:
     pass
 
-
 class Benchmark(ABC):
 
     # Override this execute method to implement the algorithm
@@ -500,10 +499,14 @@ def _finalize():
     if not loaded_from_cpp_dont_finalize:
         # Stop the Pelix framework:
         # cleaning up all Python threads that it has started.
-        serviceRegistry.framework.stop()  
-        # Wait for the framework to stop
-        serviceRegistry.framework.wait_for_stop()
-        Finalize()
+        # don't tear down if already torn down
+        try:
+            serviceRegistry.framework.stop()  
+            # Wait for the framework to stop
+            serviceRegistry.framework.wait_for_stop()
+            Finalize()
+        except NameError:
+            pass
 
 atexit.register(_finalize)