improve tests and introduce a class for the center

src/cvx/ball/solver.py

@@ -1,7 +1,7 @@
 import cvxpy as cp
 import numpy as np
 
-from .utils.circle import Circle
+from .utils.circle import Center, Circle
 
 
 def min_circle_cvx(points, **kwargs):
@@ -22,4 +22,4 @@ def min_circle_cvx(points, **kwargs):
     problem = cp.Problem(objective=objective, constraints=constraints)
     problem.solve(**kwargs)
 
-    return Circle(radius=float(r.value), center=x.value)
+    return Circle(radius=float(r.value), center=Center(x.value))

src/cvx/ball/utils/circle.py

@@ -4,12 +4,30 @@
 import plotly.graph_objects as go
 
 
+@dataclass(frozen=True)
+class Center:
+    array: np.ndarray
+
+    def __getitem__(self, item):
+        return self.array[item]
+
+    def scatter(self, **kwargs):
+        return go.Scatter(
+            x=[self[0]],
+            y=[self[1]],
+            mode="markers",
+            marker=dict(symbol="x", size=8, color="blue"),
+            name=f"Center(x = {self[0]:.2f}, y = {self[1]:.2f})",
+            **kwargs,
+        )
+
+
 @dataclass(frozen=True)
 class Circle:
-    center: np.ndarray
+    center: Center
     radius: float
 
-    def scatter(self, num=100, color="red"):
+    def scatter(self, num=800, color="red", **kwargs):
         t = np.linspace(0, 2 * np.pi, num=num)
         radius = self.radius
         circle_x = self.center[0] + radius * np.cos(t)
@@ -19,6 +37,7 @@ def scatter(self, num=100, color="red"):
             x=circle_x,
             y=circle_y,
             mode="lines",
-            line=dict(color=color, width=2),
-            name=f"Circle(r = {self.radius})",
+            line=dict(color=color, width=1),
+            name=f"Circle(r = {self.radius:.2f})",
+            **kwargs,
         )

src/cvx/ball/utils/cloud.py

@@ -8,10 +8,11 @@
 class Cloud:
     points: np.ndarray
 
-    def scatter(self, size=10):
+    def scatter(self, size=5, **kwargs):
         return go.Scatter(
             x=self.points[:, 0],
             y=self.points[:, 1],
             mode="markers",
-            marker=dict(symbol="x", size=size, color="blue"),
+            marker=dict(symbol="circle", size=size, color="black"),
+            **kwargs,
         )

src/tests/test_solver.py

@@ -1,17 +1,32 @@
 import numpy as np
+import pytest
 
 from cvx.ball.solver import min_circle_cvx
 from cvx.ball.utils.cloud import Cloud
 from cvx.ball.utils.figure import create_figure
 
 
 def test_random():
-    p = np.array([[2.0, 4.0], [0, 0], [2.5, 2.0]])
-    cloud = Cloud(p)
+    p = np.array([[2.0, 4.0], [0.0, 0.0], [2.5, 2.0]])
     circle = min_circle_cvx(p, solver="CLARABEL")
 
     fig = create_figure()
     fig.add_trace(circle.scatter())
-    fig.add_trace(cloud.scatter())
+    fig.add_trace(Cloud(p).scatter())
 
+    assert circle.radius == pytest.approx(2.2360679626271796, 1e-6)
+    assert circle.center.array == pytest.approx([1.0, 2.0], 1e-4)
     # fig.show()
+
+
+def test_graph():
+    p = np.random.randn(50, 2)
+    circle = min_circle_cvx(p, solver="CLARABEL")
+
+    fig = create_figure()
+    fig.add_trace(circle.scatter())
+    fig.add_trace(circle.center.scatter())
+    fig.add_trace(Cloud(p).scatter(name="Cloud"))
+
+    fig.update_layout(xaxis_range=[-3, 3], yaxis_range=[-3, 3])
+    fig.show()