Fix issue #16097 - Fix qasm3.dumps_experimental delay units

crates/qasm3/src/ast.rs

@@ -138,7 +138,7 @@ impl Display for DurationUnit {
         let unit_str = match self {
             DurationUnit::Nanosecond => "ns",
             DurationUnit::Microsecond => "us",
-            DurationUnit::Millisecond => "us",
+            DurationUnit::Millisecond => "ms",
             DurationUnit::Second => "s",
             DurationUnit::Sample => "dt",
         };

crates/qasm3/src/exporter.rs

@@ -1213,7 +1213,7 @@ impl<'a> QASM3Builder {
             None => {
                 if delay_unit == DelayUnit::PS {
                     DurationLiteral {
-                        value: duration * 1000.0,
+                        value: duration / 1000.0,
                         unit: DurationUnit::Nanosecond,
                     }
                 } else {

releasenotes/notes/fix-qasm3-dumps-experimental-delay-units-ac8bd64fb2c79f7d.yaml

@@ -0,0 +1,25 @@
+---
+# Delete all sections that you do not need.  You can have more than one section in a file, and
+# more than one bullet point per section.  This is a regular YAML file, and all text should use
+# Sphinx's flavor of rST (restructured text).  Each bullet point is a separate "release note".
+#
+# Each public bug fix, feature, deprecation, and behavior change needs a release note.
+# Documentation- or internal-only changes do not need release notes.
+#
+# Each bullet point appears without any context, so make sure each can be read in isolation.  The
+# reader will not see your code change, the issue, or any other bullet points in this file.  You
+# might need to repeat yourself between bullets.
+#
+# Use Sphinx cross-references like :meth:`.YourClass.your_method` whenever mentioning a
+# function/class/method by name.
+#
+# Use `- |` for multiline YAML strings (like in the "fixes" example in this template) to preserve
+# newlines, which you need for Sphinx syntax.
+#
+# There are some rare additional sections listed in `releasenotes/config.yaml` not included here.
+
+fixes:
+  - |
+    Fix qasm3.dump_experimental delay units
+
+    See ` #16097  <https://github.com/Qiskit/qiskit/issues/16097>`__.

test/python/qasm3/test_export.py

@@ -2769,6 +2769,7 @@ def test_circuit_with_unitary(self):
         self.assertEqual(test, expected)
 
 
+
 @ddt
 class TestQASM3ExporterFailurePaths(QiskitTestCase):
     """Tests of the failure paths for the exporter."""
@@ -3504,3 +3505,23 @@ def dump(self, annotation):
         )
         self.assertEqual(prog.strip(), expected.strip())
         self.assertTrue(skip_triggered)
+
+    def test_delay_units(self):
+        """Test that the `dumps_experimental` function correctly handles delay units."""
+
+        def emit(unit):
+            qc = QuantumCircuit(1)
+            qc.delay(1, 0, unit=unit)
+            out = dumps_experimental(qc)
+            line = next(l for l in out.splitlines() if "delay" in l)
+            return line.strip()
+
+        units = ["ns", "us", "ms", "s", "dt","ps"]
+        expected = "\n".join(['delay[1ns] q[0];', 
+                                'delay[1us] q[0];', 
+                                'delay[1ms] q[0];', 
+                                'delay[1s] q[0];', 
+                                'delay[1dt] q[0];', 
+                                'delay[0.001ns] q[0];'])
+
+        self.assertEqual("\n".join(emit(u) for u in units), expected)