What is first search in AI?

Encora | November 10, 2021

First search is a way to reach a goal via the shortest possible path. These search algorithms work on specific rules and use the concepts of a priority queue and heuristic search. There are a variety of first search algorithms, including Best First Search, Breadth First Search (BFS), and Depth First Search (DFS). 

Many of the AI advancements made in recent history have been made by machines playing, and beating, humans at games. Search algorithms make up the core of Artificial Intelligence (AI) programs. While they may have started as the result of playing games, these algorithms are used in many areas such as route and cost optimizations, action planning, knowledge mining, robotics, autonomous driving, computational biology, software and hardware verification, and theorem proving to name a few. Search problems can be used as a term for AI problems; for both, the task is to evaluate the problem space and outline the actions to reach the goal from the initial state through state transformation rules. If a search space is shown as a graph or tree, and the intention is to reach the goal from the initial state by way of the shortest possible path, in terms of cost, length, or a combination of both. 

All ways of search can generally be divided into two groups, uninformed or informed.

  1. Uninformed, also known as exhaustive or blind methods are where the search is done solo, without any other information, other than what is provided in the initial problem statement. Breadth First Search (BFS) and Depth First Search (DFS) are both uninformed methods.
  2. Informed, also known as heuristic methods, is where additional information is used to decide the next step in finding the solution. Best First Search is an example of an informed method. 

DFS versus BFS

Both search methods can be used to improve the efficacy of a program.

1. Depth First Search

A depth-first search is a search algorithm that travels nodes in a graph. It prioritizes searching the deepest node it knows about. It works by expanding each of the nodes it locates in a repeated manner, from the parent to the child modes. Once it has traveled to all of the nodes, it returns to the previous node and goes through the same process with each of the neighboring nodes. This type of search is used when determining if one solution among many meets certain requirements. Applications of DFS algorithms include finding connected nodes within a graph, topological organization of a directed acyclic graph, finding bridges between graph nodes, solving puzzles with a single solution, and finding strongly connected nodes. This is the type of algorithm you would use to play games and solve puzzles because each node is dependent on the previous node.  

2. Breadth First Search

Like a depth first search, a breadth first search also travels nodes in a graph. It begins at the root node, which is chosen beforehand, and then it transverses all its neighboring nodes. Each adjacent neighboring node is respectively explored until the whole graph is traversed. This style of search is best used for algorithms that need to always choose the best possible path. Applications of this style of search include finding the shortest path between two nodes, proving if a graph is able to be divided into two parts, finding the minimum expansion tree in an unweighted graph, creating a web crawler, and GPS navigation systems to find neighboring locations. For example, a GPS navigation system uses BFS algorithms to plan a trip. The tourist attractions that you want to visit are the nodes connected based on their distance from each other, and the BFS algorithm plans the shortest trip to each of those attractions. 

Encora has AI First Search Solutions for You!

If your business needs support with using First Search in AI, you’ve come to the right place. Encora helps businesses harness the power of First Search with AI to streamline productivity and increase profits. Encora recently landed on the Training Outsourcing Watch List for 2021. This means they have the expertise to train your team in AI First Search. Or, if you’d like to outsource the work to Encora, they can support you that way as well.

Whether your business needs support with Breadth First Search or Depth First Search, Encora’s teams of expert software engineers are standing by. Contact Encora today to get started!

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