RosettaCodeData/Task/Feigenbaum-constant-calculation/Fortran/feigenbaum-constant-calculation.f
2023-07-01 13:44:08 -04:00

30 lines
585 B
Fortran

program feigenbaum
implicit none
integer i, j, k
real ( KIND = 16 ) x, y, a, b, a1, a2, d1
print '(a4,a13)', 'i', 'd'
a1 = 1.0;
a2 = 0.0;
d1 = 3.2;
do i=2,20
a = a1 + (a1 - a2) / d1;
do j=1,10
x = 0
y = 0
do k=1,2**i
y = 1 - 2 * y * x;
x = a - x**2;
end do
a = a - x / y;
end do
d1 = (a1 - a2) / (a - a1);
a2 = a1;
a1 = a;
print '(i4,f13.10)', i, d1
end do
end