Merge pull request #155 from QDevil/master

QDAC2: Generalise virtual sweep

qcodes_contrib_drivers/drivers/QDevil/QDAC2.py

@@ -8,7 +8,7 @@
 from typing import Any, NewType, Sequence, List, Dict, Tuple, Optional
 from packaging.version import parse
 
-# Version 0.16.0
+# Version 0.17.0
 #
 # Guiding principles for this driver for QDevil QDAC-II
 # -----------------------------------------------------
@@ -1544,7 +1544,7 @@ def waveform(self, values: Sequence[float]) -> None:
         self._parent.write_floats(f'trac:data "{self.name}",', values)
 
 
-class Sweep_2D_Context:
+class Virtual_Sweep_Context:
 
     def __init__(self, arrangement: 'Arrangement_Context', sweep: np.ndarray,
                  start_sweep_trigger: Optional[str], inner_step_time_s: float,
@@ -1679,8 +1679,24 @@ def initiate_correction(self, gate: str, factors: Sequence[float]):
         self._correction[index] = factors
 
     def set_virtual_voltage(self, gate: str, voltage: float) -> None:
-        index = self._gate_index(gate)
+        """Set virtual voltage on specific gate
+
+        The actual voltage that the gate will receive depends on the
+        correction matrix.
+
+        Args:
+            gate (str): Name of gate
+            voltage (float): Voltage corresponding to no correction
+        """
+        try:
+            index = self._gate_index(gate)
+        except KeyError:
+            raise ValueError(f'No gate named "{gate}"')
         self._virtual_voltages[index] = voltage
+        actual_V = self.actual_voltages()[index]
+        channel_number = self._channels[index]
+        self._qdac.channel(channel_number).dc_constant_V(actual_V)
+
 
     def add_correction(self, gate: str, factors: Sequence[float]) -> None:
         """Update how much a particular gate influences the other gates
@@ -1745,45 +1761,81 @@ def get_trigger_by_name(self, name: str) -> QDac2Trigger_Context:
             print(f'Internal triggers: {list(self._internal_triggers.keys())}')
             raise
 
+    def virtual_sweep(self, gate: str, voltages: Sequence[float],
+                      start_sweep_trigger: Optional[str] = None,
+                      step_time_s: float = 1e-5,
+                      step_trigger: Optional[str] = None
+                      ) -> Virtual_Sweep_Context:
+        """Sweep a gate to create a 1D sweep
+
+        Args:
+            gate (str): Name of sweeping gate
+            voltages (Sequence[float]): Virtual sweep voltages
+            outer_gate (str): Name of slow-changing (outer) gate
+            start_sweep_trigger (None, optional): Trigger that starts sweep
+            step_time_s (float, optional): Delay between voltage changes
+            step_trigger (None, optional): Trigger that marks each step
+
+        Returns:
+            Virtual_Sweep_Context: context manager
+        """
+        sweep = self._calculate_1d_values(gate, voltages)
+        return Virtual_Sweep_Context(self, sweep, start_sweep_trigger,
+                                step_time_s, step_trigger)
+
+    def _calculate_1d_values(self, gate: str, voltages: Sequence[float]
+                            ) -> np.ndarray:
+        original_voltage = self.virtual_voltage(gate)
+        index = self._gate_index(gate)
+        sweep = []
+        for v in voltages:
+            self._virtual_voltages[index] = v
+            sweep.append(self.actual_voltages())
+        self._virtual_voltages[index] = original_voltage
+        return np.array(sweep)
+
+
     def virtual_sweep2d(self, inner_gate: str, inner_voltages: Sequence[float],
                         outer_gate: str, outer_voltages: Sequence[float],
                         start_sweep_trigger: Optional[str] = None,
                         inner_step_time_s: float = 1e-5,
                         inner_step_trigger: Optional[str] = None
-                        ) -> Sweep_2D_Context:
+                        ) -> Virtual_Sweep_Context:
         """Sweep two gates to create a 2D sweep
 
         Args:
             inner_gate (str): Name of fast-changing (inner) gate
-            inner_voltages (Sequence[float]): Inner gate voltages
+            inner_voltages (Sequence[float]): Inner gate virtual voltages
             outer_gate (str): Name of slow-changing (outer) gate
-            outer_voltages (Sequence[float]): Outer gate voltages
+            outer_voltages (Sequence[float]): Outer gate virtual voltages
             start_sweep_trigger (None, optional): Trigger that starts sweep
             inner_step_time_s (float, optional): Delay between voltage changes
             inner_step_trigger (None, optional): Trigger that marks each step
 
         Returns:
-            Sweep_2D_Context: context manager
+            Virtual_Sweep_Context: context manager
         """
-        sweep = self._calculate_sweep_values(inner_gate, inner_voltages,
+        sweep = self._calculate_2d_values(inner_gate, inner_voltages,
                                              outer_gate, outer_voltages)
-        return Sweep_2D_Context(self, sweep, start_sweep_trigger,
+        return Virtual_Sweep_Context(self, sweep, start_sweep_trigger,
                                 inner_step_time_s, inner_step_trigger)
 
-    def _calculate_sweep_values(self, inner_gate: str,
-                                inner_voltages: Sequence[float],
-                                outer_gate: str,
-                                outer_voltages: Sequence[float]) -> np.ndarray:
+    def _calculate_2d_values(self, inner_gate: str,
+                             inner_voltages: Sequence[float],
+                             outer_gate: str,
+                             outer_voltages: Sequence[float]) -> np.ndarray:
         original_fast_voltage = self.virtual_voltage(inner_gate)
         original_slow_voltage = self.virtual_voltage(outer_gate)
+        outer_index = self._gate_index(outer_gate)
+        inner_index = self._gate_index(inner_gate)
         sweep = []
         for slow_V in outer_voltages:
-            self.set_virtual_voltage(outer_gate, slow_V)
+            self._virtual_voltages[outer_index] = slow_V
             for fast_V in inner_voltages:
-                self.set_virtual_voltage(inner_gate, fast_V)
+                self._virtual_voltages[inner_index] = fast_V
                 sweep.append(self.actual_voltages())
-        self.set_virtual_voltage(inner_gate, original_fast_voltage)
-        self.set_virtual_voltage(outer_gate, original_slow_voltage)
+        self._virtual_voltages[inner_index] = original_fast_voltage
+        self._virtual_voltages[outer_index] = original_slow_voltage
         return np.array(sweep)
 
     def _gate_index(self, gate: str) -> int:

qcodes_contrib_drivers/tests/QDevil/readme.md

@@ -11,6 +11,8 @@ Simulated instrument:
     $ source venv/bin/activate
     $ pytest qcodes_contrib_drivers/tests/QDevil/test_sim_qdac2_*.py
 
+To silence warnings, use `-W ignore::DeprecationWarning`.
+
 Real instrument:
 
     $ source venv/bin/activate

qcodes_contrib_drivers/tests/QDevil/test_sim_qdac2_virtual_gates.py

@@ -11,7 +11,41 @@ def test_arrangement_default_correction(qdac):  # noqa
                           np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]]))
 
 
-def test_arrangement_default_actuals(qdac):  # noqa
+def test_arrangement_set_virtual_voltage_non_exiting_gate(qdac):  # noqa
+    arrangement = qdac.arrange(gates={'plunger': 1})
+    # -----------------------------------------------------------------------
+    with pytest.raises(ValueError) as error:
+        arrangement.set_virtual_voltage('sensor', 1.0)
+    # -----------------------------------------------------------------------
+    assert 'No gate named "sensor"' in repr(error)
+
+
+def test_arrangement_set_virtual_voltage_effectuated_immediately(qdac):  # noqa
+    arrangement = qdac.arrange(gates={'plunger1': 1, 'plunger2': 2, 'plunger3': 3})
+    qdac.start_recording_scpi()
+    # -----------------------------------------------------------------------
+    arrangement.set_virtual_voltage('plunger2', 0.5)
+    # -----------------------------------------------------------------------
+    commands = qdac.get_recorded_scpi_commands()
+    assert commands == ['sour2:volt:mode fix', 'sour2:volt 0.5']
+
+
+def test_arrangement_default_actuals_1d(qdac):  # noqa
+    arrangement = qdac.arrange(gates={'plunger1': 1, 'plunger2': 2})
+    arrangement.set_virtual_voltage('plunger2', 1.0)
+    # -----------------------------------------------------------------------
+    sweep = arrangement.virtual_sweep(
+        gate='plunger1',
+        voltages=np.linspace(-0.1, 0.1, 5),
+        step_time_s=2e-5)
+    # -----------------------------------------------------------------------
+    assert np.allclose(sweep.actual_values_V('plunger1'),
+                       [-0.1, -0.05, 0.0, 0.05, 0.1])
+    assert np.allclose(sweep.actual_values_V('plunger2'),
+                       [1.0, 1.0, 1.0, 1.0, 1.0])
+
+
+def test_arrangement_default_actuals_2d(qdac):  # noqa
     arrangement = qdac.arrange(gates={'plunger1': 1, 'plunger2': 2, 'plunger3': 3})
     # -----------------------------------------------------------------------
     sweep = arrangement.virtual_sweep2d(
@@ -186,6 +220,14 @@ def test_stability_diagram_external(qdac):  # noqa
     assert commands == [
         'outp:trig4:sour int1',
         'outp:trig4:widt 1e-06',
+        'sour3:volt:mode fix',
+        'sour3:volt 0.1',
+        'sour6:volt:mode fix',
+        'sour6:volt 0.176',
+        'sour7:volt:mode fix',
+        'sour7:volt 0.383',
+        'sour8:volt:mode fix',
+        'sour8:volt 0.69693',
         'sour3:dc:mark:sst 1',
         # Sensor 1
         'sour3:dc:trig:sour hold',