Convert QVAnalysis to use BasePlotter

Add an hline method to BaseDrawer and expose linewidth and
linestyle as series options.

Catch expected warnings about insufficient trials in analysis tests.

Remove filters preventing test failures when using the deprecated
visualization APIs.

Author: wshanks

qiskit_experiments/library/quantum_volume/qv_analysis.py

@@ -15,7 +15,7 @@
 
 import math
 import warnings
-from typing import Optional
+from typing import List, Optional
 
 import numpy as np
 import uncertainties
@@ -26,6 +26,94 @@
     AnalysisResultData,
     Options,
 )
+from qiskit_experiments.visualization import BasePlotter, MplDrawer
+
+
+class QVPlotter(BasePlotter):
+    @classmethod
+    def expected_series_data_keys(cls) -> List[str]:
+        return ["hops"]
+
+    @classmethod
+    def expected_supplementary_data_keys(cls) -> List[str]:
+        return ["depth"]
+
+    def set_supplementary_data(self, **data_kwargs):
+        if "depth" in data_kwargs:
+            self.set_figure_options(
+                figure_title=(
+                    f"Quantum Volume experiment for depth {data_kwargs['depth']}"
+                    " - accumulative hop"
+                ),
+            )
+        super().set_supplementary_data(**data_kwargs)
+
+    @classmethod
+    def _default_figure_options(cls) -> Options:
+        options = super()._default_figure_options()
+        options.xlabel = "Number of Trials"
+        options.ylabel = "Heavy Output Probability"
+        options.figure_title = "Quantum Volume experiment - accumulative hop"
+        options.series_params = {
+            "hop": {"color": "gray", "symbol": "."},
+            "threshold": {"color": "black", "linestyle": "dashed", "linewidth": 1},
+            "hop_cumulative": {"color": "r"},
+            "hop_twosigma": {"color": "lightgray"},
+        }
+        return options
+
+    @classmethod
+    def _default_options(cls) -> Options:
+        options = super()._default_options()
+        options.style["figsize"] = (6.4, 4.8)
+        options.style["axis_label_size"] = 14
+        options.style["symbol_size"] = 2
+        return options
+
+    def _plot_figure(self):
+        series = self.series[0]
+        hops, = self.data_for(series, ["hops"])
+        trials = np.arange(1, 1 + len(hops))
+        hop_accumulative = np.cumsum(hops) / trials
+        hop_twosigma = 2 * (hop_accumulative * (1 - hop_accumulative) / trials) ** 0.5
+
+        self.drawer.line(
+            trials,
+            hop_accumulative,
+            name="hop_cumulative",
+            label="Cumulative HOP",
+            legend=True,
+        )
+        self.drawer.hline(
+            2 / 3,
+            name="threshold",
+            label="Threshold",
+            legend=True,
+        )
+        self.drawer.scatter(
+            trials,
+            hops,
+            name="hop",
+            label="Individual HOP",
+            legend=True,
+            linewidth=1.5,
+        )
+        self.drawer.filled_y_area(
+            trials,
+            hop_accumulative - hop_twosigma,
+            hop_accumulative + hop_twosigma,
+            alpha=0.5,
+            legend=True,
+            name="hop_twosigma",
+            label="2σ",
+        )
+
+        self.drawer.set_figure_options(
+            ylim=(
+                max(hop_accumulative[-1] - 4 * hop_twosigma[-1], 0),
+                min(hop_accumulative[-1] + 4 * hop_twosigma[-1], 1),
+            ),
+        )
 
 
 class QuantumVolumeAnalysis(BaseAnalysis):
@@ -53,6 +141,7 @@ def _default_options(cls) -> Options:
         options = super()._default_options()
         options.plot = True
         options.ax = None
+        options.plotter = QVPlotter(MplDrawer())
         return options
 
     def _run_analysis(self, experiment_data):
@@ -77,8 +166,9 @@ def _run_analysis(self, experiment_data):
         hop_result, qv_result = self._calc_quantum_volume(heavy_output_prob_exp, depth, num_trials)
 
         if self.options.plot:
-            ax = self._format_plot(hop_result, ax=self.options.ax)
-            figures = [ax.get_figure()]
+            self.options.plotter.set_series_data("hops", hops=hop_result.extra["HOPs"])
+            self.options.plotter.set_supplementary_data(depth=hop_result.extra["depth"])
+            figures = [self.options.plotter.figure()]
         else:
             figures = None
         return [hop_result, qv_result], figures
@@ -238,73 +328,3 @@ def _calc_quantum_volume(self, heavy_output_prob_exp, depth, trials):
             },
         )
         return hop_result, qv_result
-
-    @staticmethod
-    def _format_plot(
-        hop_result: AnalysisResultData, ax: Optional["matplotlib.pyplot.AxesSubplot"] = None
-    ):
-        """Format the QV plot
-
-        Args:
-            hop_result: the heavy output probability analysis result.
-            ax: matplotlib axis to add plot to.
-
-        Returns:
-            AxesSubPlot: the matplotlib axes containing the plot.
-        """
-        trials = hop_result.extra["trials"]
-        heavy_probs = hop_result.extra["HOPs"]
-        trial_list = np.arange(1, trials + 1)  # x data
-
-        hop_accumulative = np.cumsum(heavy_probs) / trial_list
-        two_sigma = 2 * (hop_accumulative * (1 - hop_accumulative) / trial_list) ** 0.5
-
-        # Plot individual HOP as scatter
-        ax = plot_scatter(
-            trial_list,
-            heavy_probs,
-            ax=ax,
-            s=3,
-            zorder=3,
-            label="Individual HOP",
-        )
-        # Plot accumulative HOP
-        ax.plot(trial_list, hop_accumulative, color="r", label="Cumulative HOP")
-
-        # Plot two-sigma shaded area
-        ax = plot_errorbar(
-            trial_list,
-            hop_accumulative,
-            two_sigma,
-            ax=ax,
-            fmt="none",
-            ecolor="lightgray",
-            elinewidth=20,
-            capsize=0,
-            alpha=0.5,
-            label="2$\\sigma$",
-        )
-        # Plot 2/3 success threshold
-        ax.axhline(2 / 3, color="k", linestyle="dashed", linewidth=1, label="Threshold")
-
-        ax.set_ylim(
-            max(hop_accumulative[-1] - 4 * two_sigma[-1], 0),
-            min(hop_accumulative[-1] + 4 * two_sigma[-1], 1),
-        )
-
-        ax.set_xlabel("Number of Trials", fontsize=14)
-        ax.set_ylabel("Heavy Output Probability", fontsize=14)
-
-        ax.set_title(
-            "Quantum Volume experiment for depth "
-            + str(hop_result.extra["depth"])
-            + " - accumulative hop",
-            fontsize=14,
-        )
-
-        # Re-arrange legend order
-        handles, labels = ax.get_legend_handles_labels()
-        handles = [handles[1], handles[2], handles[0], handles[3]]
-        labels = [labels[1], labels[2], labels[0], labels[3]]
-        ax.legend(handles, labels)
-        return ax

qiskit_experiments/visualization/drawers/base_drawer.py

@@ -403,6 +403,30 @@ def line(
             options: Valid options for the drawer backend API.
         """
 
+    @abstractmethod
+    def hline(
+        self,
+        y_value: float,
+        name: Optional[SeriesName] = None,
+        label: Optional[str] = None,
+        legend: bool = False,
+        **options,
+    ):
+        """Draw a horizontal line.
+
+        Args:
+            y_value: Y value for line.
+            name: Name of this series.
+            label: Optional legend label to override ``name`` and ``series_params``.
+            legend: Whether the drawn area must have a legend entry. Defaults to False.
+                The series label in the legend will be ``label`` if it is not None. If
+                it is, then ``series_params`` is searched for a ``"label"`` entry for
+                the series identified by ``name``. If this is also ``None``, then
+                ``name`` is used as the fallback. If no ``name`` is provided, then no
+                legend entry is generated.
+            options: Valid options for the drawer backend API.
+        """
+
     @abstractmethod
     def filled_y_area(
         self,

qiskit_experiments/visualization/drawers/mpl_drawer.py

@@ -427,13 +427,34 @@ def line(
 
         draw_ops = {
             "color": color,
-            "linestyle": "-",
-            "linewidth": 2,
+            "linestyle": series_params.get("linestyle", "-"),
+            "linewidth": series_params.get("linewidth", 2),
         }
         self._update_label_in_options(draw_ops, name, label, legend)
         draw_ops.update(**options)
         self._get_axis(axis).plot(x_data, y_data, **draw_ops)
 
+    def hline(
+        self,
+        y_value: float,
+        name: Optional[SeriesName] = None,
+        label: Optional[str] = None,
+        legend: bool = False,
+        **options,
+    ):
+        series_params = self.figure_options.series_params.get(name, {})
+        axis = series_params.get("canvas", None)
+        color = series_params.get("color", self._get_default_color(name))
+
+        draw_ops = {
+            "color": color,
+            "linestyle": series_params.get("linestyle", "-"),
+            "linewidth": series_params.get("linewidth", 2),
+        }
+        self._update_label_in_options(draw_ops, name, label, legend)
+        draw_ops.update(**options)
+        self._get_axis(axis).axhline(y_value, **draw_ops)
+
     def filled_y_area(
         self,
         x_data: Sequence[float],

releasenotes/notes/qvplotter-04efe280aaa9d555.yaml

@@ -0,0 +1,16 @@
+---
+features:
+  - |
+    An :meth:`~qiskit_experiments.visualization.BasePlotter.hline` method was
+    added to :class:`~qiskit_experiments.visualization.BasePlotter` for
+    generating horizontal lines.
+  - |
+    The
+    :class:`~qiskit_experiments.library.quantum_volume.QuantumVolumeAnalysis`
+    analysis class was updated to use
+    :class:`~qiskit_experiments.visualization.BasePlotter` for its figure
+    generation. The appearance of the figure should be the same as in previous
+    releases. It is easier to customize the figure by setting options on the
+    plotter object, but currently the user must consult the plotter code as the
+    options are not documented. See `#1348
+    <https://github.com/Qiskit-Extensions/qiskit-experiments/pull/1348>`__.

test/base.py

@@ -106,9 +106,6 @@ def setUpClass(cls):
             # default.
             # pylint: disable=invalid-name
             allow_deprecationwarning_message = [
-                # TODO: Remove in 0.6, when submodule `.curve_analysis.visualization` is removed.
-                r".*Plotting and drawing functionality has been moved",
-                r".*Legacy drawers from `.curve_analysis.visualization are deprecated",
             ]
             for msg in allow_deprecationwarning_message:
                 warnings.filterwarnings("default", category=DeprecationWarning, message=msg)

test/library/quantum_volume/test_qv.py

@@ -13,6 +13,7 @@
 """
 A Tester for the Quantum Volume experiment
 """
+import warnings
 from test.base import QiskitExperimentsTestCase
 import json
 import os
@@ -106,15 +107,17 @@ def test_qv_sigma_decreasing(self):
 
         qv_exp = QuantumVolume(range(num_of_qubits), seed=SEED)
         # set number of trials to a low number to make the test faster
-        qv_exp.set_experiment_options(trials=2)
-        expdata1 = qv_exp.run(backend)
-        self.assertExperimentDone(expdata1)
-        result_data1 = expdata1.analysis_results(0)
-        expdata2 = qv_exp.run(backend, analysis=None)
-        self.assertExperimentDone(expdata2)
-        expdata2.add_data(expdata1.data())
-        qv_exp.analysis.run(expdata2)
-        result_data2 = expdata2.analysis_results(0)
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", message="Must use at least 100 trials")
+            qv_exp.set_experiment_options(trials=2)
+            expdata1 = qv_exp.run(backend)
+            self.assertExperimentDone(expdata1)
+            result_data1 = expdata1.analysis_results(0)
+            expdata2 = qv_exp.run(backend, analysis=None)
+            self.assertExperimentDone(expdata2)
+            expdata2.add_data(expdata1.data())
+            qv_exp.analysis.run(expdata2)
+            result_data2 = expdata2.analysis_results(0)
 
         self.assertTrue(result_data1.extra["trials"] == 2, "number of trials is incorrect")
         self.assertTrue(
@@ -145,7 +148,8 @@ def test_qv_failure_insufficient_trials(self):
         exp_data = ExperimentData(experiment=qv_exp, backend=backend)
         exp_data.add_data(insufficient_trials_data)
 
-        qv_exp.analysis.run(exp_data)
+        with self.assertWarns(UserWarning):
+            qv_exp.analysis.run(exp_data)
         qv_result = exp_data.analysis_results(1)
         self.assertTrue(
             qv_result.extra["success"] is False and qv_result.value == 1,

test/visualization/mock_drawer.py

@@ -75,6 +75,17 @@ def line(
         """Does nothing."""
         pass
 
+    def hline(
+        self,
+        y_value: float,
+        name: Optional[str] = None,
+        label: Optional[str] = None,
+        legend: bool = False,
+        **options,
+    ):
+        """Does nothing."""
+        pass
+
     def filled_y_area(
         self,
         x_data: Sequence[float],