From bdbb03e2dec4e9945c93b92fd05016c96a5da691 Mon Sep 17 00:00:00 2001
From: GabrielePalazzo <73099233+GabrielePalazzo@users.noreply.github.com>
Date: Mon, 13 Nov 2023 15:09:02 +0400
Subject: [PATCH] Improved code for selection of measurement start

---
 src/qibolab/instruments/zhinst.py | 40 ++++++++-----------------------
 1 file changed, 10 insertions(+), 30 deletions(-)

diff --git a/src/qibolab/instruments/zhinst.py b/src/qibolab/instruments/zhinst.py
index 0326349c1f..47790c7e13 100644
--- a/src/qibolab/instruments/zhinst.py
+++ b/src/qibolab/instruments/zhinst.py
@@ -892,39 +892,16 @@ def measure_relax(self, exp, qubits, relaxation_time, acquisition_type):
         """qubit readout pulse, data acquisition and qubit relaxation"""
         play_after = None
 
-        # TODO: This need to be simplified !!!
-        if len(self.sequence_qibo.qf_pulses) != 0 and len(self.sequence_qibo.qd_pulses) != 0:
-            play_after = (
-                self.play_after_set(self.sequence_qibo.qf_pulses, "bias")
-                if self.sequence_qibo.qf_pulses.finish > self.sequence_qibo.qd_pulses.finish
-                else self.play_after_set(self.sequence_qibo.qd_pulses, "drive")
-            )
-        if len(self.sequence_qibo.cf_pulses) != 0 and len(self.sequence_qibo.qd_pulses) != 0:
-            play_after = (
-                self.play_after_set(self.sequence_qibo.cf_pulses, "bias_coupler")
-                if self.sequence_qibo.cf_pulses.finish > self.sequence_qibo.qd_pulses.finish
-                else self.play_after_set(self.sequence_qibo.qd_pulses, "drive")
-            )
+        qf_finish = self.sequence_qibo.qf_pulses.finish
+        qd_finish = self.sequence_qibo.qd_pulses.finish
+        cf_finish = self.sequence_qibo.cf_pulses.finish
 
-        elif len(self.sequence_qibo.qf_pulses) != 0:
+        if qf_finish > qd_finish and qf_finish > cf_finish:
             play_after = self.play_after_set(self.sequence_qibo.qf_pulses, "bias")
-        elif len(self.sequence_qibo.qd_pulses) != 0:
+        elif qd_finish > qf_finish and qd_finish > cf_finish:
             play_after = self.play_after_set(self.sequence_qibo.qd_pulses, "drive")
-        elif (
-            len(self.sequence_qibo.qf_pulses) != 0
-            and len(self.sequence_qibo.qd_pulses) != 0
-            and len(self.sequence_qibo.cf_pulses) != 0
-        ):
-            seq_qf = self.sequence_qibo.qf_pulses.finish
-            seq_qd = self.sequence_qibo.qd_pulses.finish
-            seq_cf = self.sequence_qibo.cf_pulses.finish
-            # add here for flux coupler pulses
-            if seq_qf > seq_qd and seq_qf > seq_cf:
-                play_after = self.play_after_set(self.sequence_qibo.qf_pulses, "bias")
-            elif seq_qd > seq_qf and seq_qd > seq_cf:
-                play_after = self.play_after_set(self.sequence_qibo.qd_pulses, "drive")
-            elif seq_cf > seq_qf and seq_cf > seq_qd:
-                play_after = self.play_after_set(self.sequence_qibo.cf_pulse, "bias_coupler")
+        elif cf_finish > qf_finish and cf_finish > qd_finish:
+            play_after = self.play_after_set(self.sequence_qibo.cf_pulses, "bias_coupler")
 
         readout_schedule = defaultdict(list)
         qubit_readout_schedule = defaultdict(list)
@@ -948,6 +925,9 @@ def measure_relax(self, exp, qubits, relaxation_time, acquisition_type):
                 for pulse, q, iq_angle in zip(pulses, qubits, iq_angles):
                     pulse.zhpulse.uid += str(i)
 
+                    # TODO: if the measure sequence starts after the last pulse, add a delay
+                    # if the delay is too large (i.e. 5us),
+                    # throw an exception / no delay / maximum delay possible
                     if play_after is None:
                         exp.delay(
                             signal=f"measure{q}",