Fortraneries/Fraktalism/henon.f90
2024-03-10 06:56:29 +01:00

46 lines
941 B
Fortran

module henon
implicit none
contains
!-----------------------------------------------------
subroutine compute_pixel_henon(a, b, maxpasse, passe, limit, rx, ry)
implicit none
double precision, intent(in) :: a, b, limit
integer, intent(in) :: maxpasse
integer, intent(out) :: passe
double precision, intent(out) :: rx, ry
double precision :: x, y, x2, y2
write(0, fmt="('compute pixel:', (2F8.3, I6, F8.3))") &
a, b, maxpasse, limit
x = 0.0
y = 0.0
do passe=1, maxpasse
x2 = 1d0 + y - (a * x * x)
y2 = b * x
x = x2
y = y2
write(0, fmt="(i4, 2F8.3)") passe, x, y
if (x .lt. -limit) exit
if (x .gt. limit) exit
if (y .lt. -limit) exit
if (y .gt. limit) exit
enddo
rx = x
ry = y
end subroutine
!-----------------------------------------------------
end module