I can't understand how the squarifyRatio works

[officialBusiness]

d3-hierarchy => treemap => squarify.js

I don't know what alpha and bata mean, why alpha is Math.max(dy / dx, dx / dy) / (value * ratio) and beta is sumValue * sumValue * alpha.
I also want to know why ratio is Math.max(maxValue / beta, beta / minValue)
I've learn about squarify's algorithm briefly, but I don't understand how your code implements the length allocation of child nodes on an edge.
I'm tired. hlep