说明：  比如每个企业和个人都要考虑的一个问题“在一定成本下，如何使利润最大化”等。最优化方法是一种数学方法，它是研究在给定约束之下如何寻求某些因素(的量)，以使某一(或某些)指标达到最优的一些学科的总称。随着学习的深入，博主越来越发现最优化方法的重要性，学习和工作中遇到的大多问题都可以建模成一种最优化模型进行求解，比如我们现在学习的机器学习算法，大部分的机器学习算法的本质都是建立优化模型，通过最优化方法对目标函数（或损失函数）进行优化，从而训练出最好的模型。常见的最优化方法有梯度下降法、牛顿法和拟牛顿法、共轭梯度法等等。
(For example, every enterprise and individual should consider a problem "how to maximize profit at a certain cost." The optimization method is a mathematical method. It is a general term for some disciplines that study how to find certain factors (quantity) under a given constraint to make one (or some) index get the best. With the in-depth study, the blogger found more and more importance of optimization methods, have to study and work in most of the problems can be modeled as solving an optimization model, such as we are now learning machine learning algorithm, most of the machine learning algorithm is the essence of optimization model is established through the optimization method of the objective function (or the loss function) optimization, to train a best model. The common optimization methods include gradient descent method, Newton method and quasi Newton method, conjugate gradient method and so on.)