Fortran Wiki
random_init

Description

Initializes the state of the pseudorandom number generator used by random_number.

Standard

Fortran 2018

Class

Subroutine

Syntax

call random_init(repeatable, image_distinct)

Arguments

• repeatable - Shall be a scalar with a logical type, and it is intent(in). If it is .true., the seed is set to a processor-dependent value that is the same each time random_init is called from the same image. The term “same image” means a single instance of program execution. The sequence of random numbers is different for repeated execution of the program. If it is .false., the seed is set to a processor-dependent value.
• image_distinct - Shall be a scalar with a logical type, and it is intent(in). If it is .true., the seed is set to a processor-dependent value that is distinct from the seed set by a call to random_init in another image. If it is .false., the seed is set value that does depend which image called random_init.

Example

program test_random_seed
  implicit none
  real x(3), y(3)
  call random_init(.true., .true.)
  call random_number(x)
  call random_init(.true., .true.)
  call random_number(y)
  ! x and y are the same sequence
  if (any(x /= y)) stop "x(:) and y(:) not all equal"
end program test_random_seed

See also

random_number, random_seed