#!/usr/local/bin/ruby # frozen_string_literal: false # # nlsolve.rb # An example for solving nonlinear algebraic equation system. # require "bigdecimal" require "bigdecimal/newton" include Newton class Function # :nodoc: all def initialize() @zero = BigDecimal("0.0") @one = BigDecimal("1.0") @two = BigDecimal("2.0") @ten = BigDecimal("10.0") @eps = BigDecimal("1.0e-16") end def zero;@zero;end def one ;@one ;end def two ;@two ;end def ten ;@ten ;end def eps ;@eps ;end def values(x) # <= defines functions solved f = [] f1 = x[0]*x[0] + x[1]*x[1] - @two # f1 = x**2 + y**2 - 2 => 0 f2 = x[0] - x[1] # f2 = x - y => 0 f <<= f1 f <<= f2 f end end f = BigDecimal.limit(100) f = Function.new x = [f.zero,f.zero] # Initial values n = nlsolve(f,x) p x