maths_mod Module Reference

Functions/Subroutines
real(kind=default_precision) function, public	random (idum)
	returns a scalar random number, the initial seed idum must be negative usage: idum = -k !(set idum < 0 to initialise) do i=1,nvals my_rand(i) = random(idum) end do More...

Variables
integer, parameter	k4b =selected_int_kind(9)
integer(k4b), parameter	ia =16807
integer(k4b), parameter	im =2147483647
integer(k4b), parameter	iq =127773
integer(k4b), parameter	ir =2836

Function/Subroutine Documentation

random()

real(kind=default_precision) function, public maths_mod::random

(

integer(k4b), intent(inout)

idum

)

returns a scalar random number, the initial seed idum must be negative usage: idum = -k !(set idum < 0 to initialise) do i=1,nvals my_rand(i) = random(idum) end do

Parameters

idum	Initial seed which must be negative

Definition at line 22 of file maths.F90.

    integer(k4b),intent(inout) :: idum
        
    real,save :: am
    integer(k4b), save :: ix=-1,iy=-1,k
 
    if (idum <=0 .or. iy < 0) then
      am = nearest(1.0,-1.0)/im
      iy=ior(ieor(888889999,abs(idum)),1)
      ix=ieor(777755555,abs(idum))
      idum=abs(idum)+1
    end if
    ix = ieor(ix,ishft(ix,13))
    ix = ieor(ix,ishft(ix,-17))
    ix = ieor(ix,ishft(ix,5))
    k=iy/iq
    iy=ia*(iy-k*iq)-ir*k
    if(iy < 0) iy = iy + im
    random = am*ior(iand(im,ieor(ix,iy)),1)

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Variable Documentation

ia

integer(k4b), parameter maths_mod::ia =16807

private

Definition at line 10 of file maths.F90.

  integer(k4b), parameter :: ia=16807,im=2147483647

im

integer(k4b), parameter maths_mod::im =2147483647

private

Definition at line 10 of file maths.F90.

iq

integer(k4b), parameter maths_mod::iq =127773

private

Definition at line 11 of file maths.F90.

  integer(k4b), parameter :: iq=127773,ir=2836

ir

integer(k4b), parameter maths_mod::ir =2836

private

Definition at line 11 of file maths.F90.

k4b

integer, parameter maths_mod::k4b =selected_int_kind(9)

private

Definition at line 9 of file maths.F90.

  integer, parameter :: k4b=selected_int_kind(9)