Unbias a random generator: Difference between revisions
added Fortran
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Line 58:
5: 19.61% 50.01%
6: 16.70% 49.98%</pre>
=={{header|Fortran}}==
{{works with|Fortran|90 and later}}
<lang fortran>program Bias_Unbias
implicit none
integer, parameter :: samples = 1000000
integer :: i, j
integer :: c1, c2, rand
do i = 3, 6
c1 = 0
c2 = 0
do j = 1, samples
rand = bias(i)
if (rand == 1) c1 = c1 + 1
rand = unbias(i)
if (rand == 1) c2 = c2 + 1
end do
write(*, "(i2,a,f8.3,a,f8.3,a)") i, ":", real(c1) * 100.0 / real(samples), &
"%", real(c2) * 100.0 / real(samples), "%"
end do
contains
function bias(n)
integer :: bias
integer, intent(in) :: n
real :: r
call random_number(r)
if (r > 1 / real(n)) then
bias = 0
else
bias = 1
end if
end function
function unbias(n)
integer :: unbias
integer, intent(in) :: n
integer :: a, b
do
a = bias(n)
b = bias(n)
if (a /= b) exit
end do
unbias = a
end function
end program</lang>
Output:
<pre>3: 33.337% 49.971%
4: 24.945% 49.944%
5: 19.971% 49.987%
6: 16.688% 50.097%</pre>
=={{header|J}}==
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