Finding the minimum ratio cut or normalised cut is computationally prohibitive approximation is often used

One popular approximation algorithm is the spectral clustering algorithm, which involves computing the eigenvectors of the graph Laplacian matrix and using them to partition the graph. Another approach is the recursive bisection algorithm, where the graph is recursively divided into two parts based on the minimum ratio cut until a desired number of partitions is reached. These approximation algorithms can provide good results with reasonable computational cost.