chrsstrm

/**
 * create a Google Sheet then go to Tools > Script Editor
 * Paste this code into the editor. Save. 
 * Publish > Deploy as Web App
 * Set new version, publish as me, who has access - anyone, even anon.
 * GET to the URL, add on end ?sheet=[sheet name]
 * Sheet name is the sheet name, manage appropriately (no spaces or symbols to keep it simple)
 * Request returns JSON representation of the sheet.
 */

Serabe

require 'matrix'

def regression x, y, degree
  x_data = x.map {|xi| (0..degree).map{|pow| (xi**pow) }}
  mx = Matrix[*x_data]
  my = Matrix.column_vector y

  ((mx.t * mx).inv * mx.t * my).transpose.to_a[0].reverse
end