Visual Turing Machine 2.0

Visual Turing Machine (VTM) is a software tool that will help you to visually design Turing machines.

This means no coding in abstract scripting languages, but simple point & click design. Visual Turing uses only the * and | symbols, and also simulates an infinite tape.

Turing machines are abstract mathematical devices. They consist of an infinite tape, with each cell of the tape containing one symbol. The Turing machine writes on this tape.

The usability of Turing machines is that it includes conditionality when to write a symbol, as well as the option to move the tape left and right. This behaviour enables it to perform any existing algorithm, no matter how complex that algorithm is.

Visual Turing is a visual implementation of this abstract machine, and tries to simulate an infinite tape. Besides the basic functionality, Visual Turing adds some other functionality to ease the development of Turing machines.

Visual Turing includes some special features which are not strictly correct in theory, but will make your life easier. Lets say you want to make a achine which moves 5 cells to the right.

You would normally draw 5 Right instructions and connect them. You can save time by simply drawing 1 Right instruction and set how many times should it get repeated. Right-click on the instruction (or machine) and click on Set N. A dialog will show up where you have to enter a number greater than 1.

For example, enter 5, and your instruction will get executed 5 times. You can also enter an expression, like n+5. The n number is indicated by a small number on the right side of the instruction.

You may want to create a machine that executes actions several times, but you dont want to define exactly how many times. For example, you want to create a Right machine, but you want to be asked each time how many cells should it go to the right.

In this case, open the Set N dialog, and instead of typing in a number, type in n. This means the machine is using an undefined variable. When you execute your machine, you will get asked about the value of n.

To use an n-machine, export your machine. When you later import these machines and you want to use them, you will get asked about the value of n.