WIP on scheduling with control flow instructions.

QGL/Scheduler.py

@@ -2,6 +2,7 @@
 from .Channels import Edge
 from .PulseSequencer import PulseBlock
 from .ControlFlow import Barrier, ControlInstruction
+from .BlockLabel import BlockLabel
 from .PatternUtils import flatten
 from warnings import warn
 
@@ -21,11 +22,15 @@ def schedule(seq):
         if isinstance(instr, Barrier):
             synchronize_counters(counters, instr.chanlist)
             continue
-        channels = get_channels(instr)
-        # find the most advanced counter in the channel set
-        idx = max(counters.get(ch, 0) for ch in channels)
+        if isinstance(instr, (ControlInstruction, BlockLabel)):
+            channels = counters.keys()
+            idx = len(out_seq)
+        else:
+            channels = get_channels(instr)
+            # find the most advanced counter in the channel set
+            idx = max(counters.get(ch, 0) for ch in channels)
 
-        if idx > len(out_seq) - 1:
+        if (idx > len(out_seq) - 1) or isinstance(out_seq[idx], ControlInstruction):
             out_seq.append(instr)
         else:
             out_seq[idx] *= instr

tests/test_Scheduler.py

@@ -77,4 +77,25 @@ def test_2q_ops(self):
     def test_controlflow(self):
         # TODO to do this properly we need ControlInstructions to be valid operands
         # in tensor products, i.e. we want qif(..) * qif(...) to be valid
-        pass
+        q1, q2, q3, q4 = self.q1, self.q2, self.q3, self.q4
+
+        seq = [X(q1),X(q2),
+               CNOT(q1,q2)] + \
+              qif(1, [Y(q1),Y(q2),X90(q1)], [Z(q1),Z(q2),X90(q1)]) + \
+              [Y90(q1),Y90(q2)]
+
+        result = schedule(seq)
+        assert(result == [X(q1) * X(q2),
+                          CNOT(q1, q2)] + \
+                         qif(1, [Y(q1)*Y(q2), X90(q1)], [Z(q1)*Z(q2), X90(q1)]) + \
+                         [Y90(q1) * Y90(q2)])
+
+        # test that "global" control flow injects barriers
+        seq = [X(q1)] + \
+              qif(1, [Y(q1),Y(q2),X90(q1)], [Z(q1),Z(q2),X90(q1)]) + \
+              [Y90(q1),Y90(q2)]
+
+        result = schedule(seq)
+        assert(result == [X(q1)] + \
+                         qif(1, [Y(q1)*Y(q2), X90(q1)], [Z(q1)*Z(q2), X90(q1)]) + \
+                         [Y90(q1) * Y90(q2)])