Update 'Getting Started'

docs/start.rst

@@ -65,12 +65,12 @@ Using the API
 
 Qrack API methods operate on "QEngine" and "QUnit" objects. ("QUnit" objects are a specific optional optimization on "QEngine" objects, with the same API interface.) These objects are organized as 1-dimensional arrays of coherent qubits which can be arbitrarily entangled within the QEngine or QUnit. These object have methods that act like quantum gates, for a specified qubit index in the 1-dimensional array, as well as any analog parameters needed for the gate (like for variable angle rotation gates). Many fundamental gate methods have variants that are optimized to act on a contiguous length of qubits in the array at once. For OpenCL ``QEngineOCL`` objects, the preferred OpenCL device can be specified in the constructor. For multiprocessor ``QEngineOCLMulti`` engines, you can specify distribution of equal-sized sub-engines between available OpenCL devices. See the API reference for more details.
 
-To create a QEngine or QUnit object, you can use the factory provided in include/qfactory.hpp:
+To create a QEngine or QUnit object, you can use the factory provided in include/qfactory.hpp. The easiest way to choose an optimal "layer stack" is to use `QINTERFACE_OPTIMAL` for a single OpenCL device simulator, and use `QINTERFACE_OPTIMAL_MULTI` for a multi-device simulator:
 
 .. code-block:: c
 
-    QInterfacePtr qftReg = CreateQuantumInterface(QINTERFACE_QUNIT, QINTERFACE_STABILIZER_HYBRID, qubitCount, intPerm, rng);
-    QInterfacePtr qftReg2 = CreateQuantumInterface(QINTERFACE_OPENCL, QINTERFACE_STABILIZER_HYBRID, qubitCount, intPerm, rng);
+    QInterfacePtr qftReg = CreateQuantumInterface(QINTERFACE_OPTIMAL, qubitCount, intPerm, rng);
+    QInterfacePtr qftReg2 = CreateQuantumInterface(QINTERFACE_OPTIMAL_MULTI, qubitCount, intPerm, rng);
 
 By default, the ``Qrack::OCLEngine`` singleton attempts to compile kernels and initialize supporting OpenCL objects for all devices on a system. You can strike devices from the list to free their OpenCL resources, usually before initializing OpenCL QEngine objects: