Fix wrong input dimension for decision region plot

constellation/util.py

@@ -101,9 +101,12 @@ def plot_constellation(
     # Plot decision regions
     regions_extent = 2 * axis_extent
     step = grid_step * regions_extent
+
     grid_range = torch.arange(-regions_extent, regions_extent, step)
     grid_y, grid_x = torch.meshgrid(grid_range, grid_range)
-    grid_images = decoder(torch.stack((grid_x, grid_y), dim=2)).argmax(dim=2)
+
+    grid_points = torch.stack((grid_x, grid_y), dim=-1).flatten(end_dim=1)
+    grid_images = decoder(grid_points).argmax(dim=-1).reshape(grid_x.shape)
 
     ax.imshow(
         grid_images,