Objective Functionis a function of the design variables, which is usually used to express the target form pursued.

The form of the objective function

• Maximizing the posterior probability MAP: such as Naive Bayes
• Maximizing fitness function: such as genetic algorithm
• Maximizing a reward/value function: such as reinforcement learning
• Maximize information gain/reduce child node purity: such as CART decision tree classifier
• Minimize the squared error cost function: such as CART, decision tree regression, linear regression, linear adaptive neuron
• Maximize similarity or minimize information entropy loss function
• Minimize hinge loss function: such as support vector machine SVM