What is the lifetime of a variable?

When we first run the tf.Variable.initializer operation for a variable in a session, it is started. It is destroyed when we run the tf.Session.close operation.

The lifetime of a variable refers to the duration during which the variable exists in the memory of a program. The specific lifetime of a variable depends on its scope and storage duration.

  1. Scope: Scope determines where in the program a variable can be accessed. Variables can have local or global scope.
    • Local variables exist only within the block of code in which they are defined (e.g., within a function). Their lifetime starts when the block is entered and ends when the block is exited.
    • Global variables, on the other hand, exist throughout the entire program. Their lifetime starts when the program begins execution and ends when the program terminates.
  2. Storage Duration: Storage duration determines when memory is allocated for the variable and when it is deallocated.
    • Variables can have static, automatic, or dynamic storage duration.
      • Static variables have a fixed memory allocation throughout the program’s execution, and their lifetime is the entire runtime of the program.
      • Automatic variables are allocated when the block containing them is entered and deallocated when the block is exited. Their lifetime is limited to the scope of the block.
      • Dynamic variables are allocated and deallocated explicitly by the programmer and can have varying lifetimes depending on how they are managed.

In summary, the correct answer would be that the lifetime of a variable depends on its scope and storage duration, ranging from the entire duration of a program’s execution for global variables to the duration of a specific block of code for local variables, with variations based on storage duration.