Add detailed instructions for implementing predator behavior in Vicsek model

Author: Daniel Precioso, PhD

modules/collective-motion/vicsek-predator.qmd

@@ -23,6 +23,15 @@ The simplest case is a predator fixed at a given position. To implement this:
 - Pass `xy_pred` to your Vicsek update at each frame.
 - Draw the predator in the plotting section (after initializing the axes).
 
+::: {.callout-tip collapse="true"}
+## Where to include the code
+
+- **Set `xy_pred` before the animation loop**: In `run_simulation`, set `xy_pred = np.array([box_size/2, box_size/2])` (or wherever you want the static predator) before entering the animation.
+- **Pass `xy_pred` to the Vicsek update**: In the `update_animation` function, pass `xy_pred` as an argument to `vicsek_equations`.
+- **Draw the predator**: After initializing the axes in `run_simulation`, add the predator circle with `circle_predator = plt.Circle(xy_pred, radius_predator, color="red", fill=False)` and `ax_plane.add_artist(circle_predator)`.
+- **Update the predator's position in the plot (if needed)**: For a static predator, this is only needed once. For moving predators, update `circle_predator.set_center(xy_pred)` in each animation frame.
+:::
+
 ---
 
 ## Random Walk Predator