The functions of the drum machine are: organize rhythm, fill in music, start and end points, switch music styles, and improve the sense of rhythm.

1. Organize rhythm: The drum machine is one of the most important rhythm parts among accompaniment instruments. It can provide a stable rhythm and help musicians grasp the rhythm and maintain synchronization.

2. Filling in music: The drum machine can fill in the blank parts of the music, making the music richer and full of tension.

3. Starting point and end point: Drum machines are often used to mark the beginning and end of music, as well as transitional parts.

4. Switch music styles: Different types of music have their own specific rhythms and drumming methods, and drum machines can be used to switch between different styles of music.

5. Improve the sense of rhythm: Playing a drum machine allows percussionists to better grasp the sense of rhythm, and can help players of other instruments grasp the rhythm more accurately.