Difference between Finite Automata and Turing Machine
Last Updated :
27 Sep, 2022
1. Finite Automata: The finite automata or finite state machine is an abstract machine that has five elements or tuples. It has a set of states and rules for moving from one state to another but it depends upon the applied input symbol. Basically, it is an abstract model of a digital computer. The following figure shows some essential features of general automation.
Figure : Features of Finite Automata
The above figure shows the following features of automata :
- Input
- Output
- States of automata
- State relation
- Output relation
2. Turing Machine: It is a powerful model which was proposed by Alan Turing in 1936. The earlier models like finite automata and push-down automata are not considered accurate models because they cannot recognize the simple language. But the turing machine is the most accurate model for personal computers. A turing machine is capable of solving every problem that a real computer can do. There are also some problems which can not be solved by turing machines because these problems are beyond the theoretical limits of computation.
Figure: Turing Machine Model
Difference between Finite Automata and Turing Machine:
Finite Automata |
Turing Machine |
It recognizes the language called regular language. |
It will recognize not only regular language but also context-free language, context-sensitive language, and recursively enumerable languages. |
In this, the input tape is of finite length from both the left and right sides. |
In this, the input tape is of finite length from the left but is of infinite length from the right. |
It consists of a finite number of states, a finite set of input symbols, an initial state of automata, and a finite set of transition rules for moving from one state to another. |
It also contains a finite set of tape symbols and a blank symbol on the tape in addition to a finite number of states, a finite set of input symbols, an initial state of automata, and a finite set of transition rules for moving from one state to another. |
In this head is able to move in the right direction only. In two-way automata, the head is able to move in both directions. |
In this, the head can move in both directions. |
The Head is only able to read the symbols from the tape but can not write symbols on the tape. |
The Head is able to read as well as write symbols on the tape. |
It is weak as compared to Turing Machine. |
It is more powerful than Finite Automata. |
Designing finite automata is easier. |
Designing turing machine is difficult and as well as complex. |
The transition function in finite automata can be represented by: δ : Q × Σ* → Q |
The transition function in turing machine can be represented by: δ : Q × T → Q × T × {L, R} where L and R specify the left and right movement of the tape head. |
Finite state machines have lower computational power than the Turing machine. |
Turing machines have more computational power than FSM. |
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