The Music of Graphs

Can you hear the shape of a graph? It turns out graphs have spectra, which can be computed by representing the graph as a matrix, and computing the eigenvalues.

In this example, we compute the normalised Laplacian matrix for a given graph, then map its eigenvalues onto two octaves: 0 becomes 440 Hz (A), 1 becomes 880 Hz (A again), and finally, 2 becomes 1760 Hz.

Instructions

To add a new vertex, first select the vertex you want to connect it to. Then shift-click (ctrl-click or alt-click will also work). You can shift-click on an existing vertex to connect it to a selected vertex.

To delete a vertex, press delete or backspace.

Do you notice any relationship between symmetry in the graph and the harmoniousness of the chord?

Graph Spectrum

Laplacian Matrix

Credits and Further Reading

Built with D3.