Fixes to various graphs in the docs (#14055)

* Fixes to various graphs in the docs

* Fix a bug caused by `tight_layout` crashing on some images

* Apply the fix to the timeline plotter

* Remove release note and fix bloch sphere visualization

* Additional bloch fix

* Slighly relax image compairson for bloch sphere due to small discrepancies between the server and local versions.

Author: gadial

qiskit/circuit/library/graph_state.py

@@ -48,6 +48,7 @@ class GraphState(QuantumCircuit):
        import rustworkx as rx
        G = rx.generators.cycle_graph(5)
        circuit = GraphState(rx.adjacency_matrix(G))
+       circuit.name = "Graph state"
        _generate_circuit_library_visualization(circuit)
 
     **References:**

qiskit/visualization/counts_visualization.py

@@ -408,6 +408,10 @@ def _plotting_core(
     if fig:
         matplotlib_close_if_inline(fig)
     if filename is None:
+        try:
+            fig.tight_layout()
+        except AttributeError:
+            pass
         return fig
     else:
         return fig.savefig(filename)

qiskit/visualization/library.py

@@ -23,15 +23,18 @@ def _generate_circuit_library_visualization(circuit: QuantumCircuit):
     import matplotlib.pyplot as plt
 
     circuit = circuit.decompose()
+    global_phase, circuit.global_phase = circuit.global_phase, 0
     ops = circuit.count_ops()
     num_nl = circuit.num_nonlocal_gates()
-    _fig, (ax0, ax1) = plt.subplots(2, 1)
+    _fig, (ax0, ax1) = plt.subplots(2, 1, figsize=(6.4, 9.6))
     circuit.draw("mpl", ax=ax0)
+    circuit.global_phase = global_phase
     ax1.axis("off")
     ax1.grid(visible=None)
     ax1.table(
         [[circuit.name], [circuit.width()], [circuit.depth()], [sum(ops.values())], [num_nl]],
         rowLabels=["Circuit Name", "Width", "Depth", "Total Gates", "Non-local Gates"],
+        loc="top",
     )
     plt.tight_layout()
     plt.show()

qiskit/visualization/state_visualization.py

@@ -281,7 +281,8 @@ def plot_bloch_multivector(
         reverse_bits (bool): If True, plots qubits following Qiskit's convention [Default:False].
         font_size (float): Font size for the Bloch ball figures.
         title_font_size (float): Font size for the title.
-        title_pad (float): Padding for the title (suptitle `y` position is `y=1+title_pad/100`).
+        title_pad (float): Padding for the title (suptitle `y` position is `0.98`
+        and the image height will be extended by `1 + title_pad/100`).
 
     Returns:
         :class:`matplotlib:matplotlib.figure.Figure` :
@@ -345,6 +346,8 @@ def plot_bloch_multivector(
         width *= num
     else:
         width, height = plt.figaspect(1 / num)
+    if len(title) > 0:
+        height += 1 + title_pad / 100  # additional space for the title
     default_title_font_size = font_size if font_size is not None else 16
     title_font_size = title_font_size if title_font_size is not None else default_title_font_size
     fig = plt.figure(figsize=(width, height))
@@ -354,9 +357,13 @@ def plot_bloch_multivector(
         plot_bloch_vector(
             bloch_data[i], "qubit " + str(pos), ax=ax, figsize=figsize, font_size=font_size
         )
-    fig.suptitle(title, fontsize=title_font_size, y=1.0 + title_pad / 100)
+    fig.suptitle(title, fontsize=title_font_size, y=0.98)
     matplotlib_close_if_inline(fig)
     if filename is None:
+        try:
+            fig.tight_layout()
+        except AttributeError:
+            pass
         return fig
     else:
         return fig.savefig(filename)
@@ -726,6 +733,10 @@ def plot_state_paulivec(state, title="", figsize=None, color=None, ax=None, *, f
     if return_fig:
         matplotlib_close_if_inline(fig)
     if filename is None:
+        try:
+            fig.tight_layout()
+        except AttributeError:
+            pass
         return fig
     else:
         return fig.savefig(filename)

qiskit/visualization/timeline/plotters/matplotlib.py

@@ -188,5 +188,8 @@ def get_image(self, interactive: bool = False) -> matplotlib.pyplot.Figure:
 
         if self.figure and interactive:
             self.figure.show()
-
+        try:
+            self.figure.tight_layout()
+        except AttributeError:
+            pass
         return self.figure

test/visual/mpl/graph/references/bloch_multivector.png

@@ -113,7 +113,7 @@ def test_plot_bloch_multivector(self):
             FAILURE_DIFF_DIR,
             FAILURE_PREFIX,
         )
-        self.assertGreaterEqual(ratio, 0.99, msg=fname)
+        self.assertGreaterEqual(ratio, 0.98, msg=fname)
 
     def test_plot_state_hinton(self):
         """test plot_state_hinton"""
@@ -650,15 +650,14 @@ def test_plot_bloch_multivector_figsize_improvements(self):
             title_pad=8,
             filename=fname,
         )
-
         ratio = VisualTestUtilities._save_diff(
             self._image_path(fname),
             self._reference_path(fname),
             fname,
             FAILURE_DIFF_DIR,
             FAILURE_PREFIX,
         )
-        self.assertGreaterEqual(ratio, 0.99, msg=fname)
+        self.assertGreaterEqual(ratio, 0.98, msg=fname)
 
 
 if __name__ == "__main__":