chore: review comments

src/qibolab/pulses/plot.py

@@ -143,6 +143,8 @@ def sequence(ps: PulseSequence, freq: dict[str, float], filename=None):
         import matplotlib.pyplot as plt
         from matplotlib import gridspec
 
+        # compile ``Align`` to delays as it is not supported here
+        ps = ps.align_to_delays()
         num_pulses = len(ps)
         _ = plt.figure(figsize=(14, 2 * num_pulses), dpi=200)
         gs = gridspec.GridSpec(ncols=1, nrows=num_pulses)

src/qibolab/sequence.py

@@ -78,14 +78,9 @@ def channel_duration(self, channel: ChannelId) -> float:
         """Duration of the given channel."""
         return sum(pulse.duration for pulse in self.channel(channel))
 
-    def pulse_channels(self, pulse_id: int) -> ChannelId:
+    def pulse_channels(self, pulse_id: int) -> list[ChannelId]:
         """Find channels on which a pulse with a given id plays."""
-        channels = [channel for channel, pulse in self if pulse.id == pulse_id]
-        if len(channels) == 0:
-            raise ValueError(
-                f"Pulse with id {pulse_id} does not exist in the sequence."
-            )
-        return channels
+        return [channel for channel, pulse in self if pulse.id == pulse_id]
 
     def concatenate(self, other: "PulseSequence") -> None:
         """Juxtapose two sequences.

tests/pulses/test_sequence.py

@@ -194,6 +194,11 @@ def test_align_to_delay():
     for (ch1, p1), (ch2, p2) in zip(sequence[7:], delay_sequence[6:]):
         assert ch1 == ch2
         assert p1 is p2
+    # assert that pulses after align start simultaneously
+    sequence_without_last = PulseSequence(delay_sequence[:-2])
+    ch1_start = sequence_without_last.channel_duration("ch1")
+    ch2_start = sequence_without_last.channel_duration("ch2")
+    assert ch1_start == ch2_start
 
 
 def test_trim():