[Shootout-list] f90 version of mandelbrot
Simon Geard
simon@whiteowl.co.uk
Sat, 08 Jan 2005 09:32:35 +0000
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Attached. It uses the built-in complex data-type. On my system it gives
the very similar results to the c version:
[simon@fawkes f90]$ time -p mandelbrot.gcc_run 1000 > outc.pbm
real 0.45
user 0.41
sys 0.00
[simon@fawkes f90]$ time -p mandelbrot 1000 > out.pbm
real 0.45
user 0.43
sys 0.00
Simon
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filename="mandelbrot.f90"
!!$/* The Great Computer Language Shootout
! http://shootout.alioth.debian.org/
!
! Simon Geard, 6/1/05
!
! Adapted mandelbrot.c by Greg Buchholz
!
! Building info.
! ==============
!
! Linux - using the Intel Fortran90 compiler:
!
! ifort mandelbrot.f90 -O3 -static-libcxa -o mandelbrot
!
! WinXP - Compaq Visual Fortran 6.6c
!
! f90 mandelbrot.f90 /link /libpath:"d:\Program Files\Microsoft Visual Studio\df98\lib"
!
! Cygwin - g95 compiler
!
! g95 mandelbrot.f90 -O3 -o mandelbrot.exe
!
program mandelbrot
implicit none
integer w, h, x, y, bit_num
integer(kind=1) byte_acc
integer(kind=1), parameter :: K0 = 0
integer(kind=1), parameter :: K1 = 1
integer, parameter :: iter = 50
real*8, parameter :: limit2 = 4.0d0
integer i
character(len=8) argv
complex(kind=8) Z, C
logical debug, in_mandelbrot
call getarg(1,argv)
read(argv,*) w
h = w
bit_num = 0
byte_acc = K0
! Output pbm header
write(*,'(a)') 'P4'
write(*,'(i0,a,i0)') w,' ',h
do y=0,h-1
do x=0,w-1
C = cmplx(2.0d0*x/w-1.5d0,2.0d0*y/h-1.0d0)
Z = (0.0d0,0.0d0)
in_mandelbrot = .true.
do i=0,iter-1
Z = Z**2 + C
if (real(Z*conjg(Z)) > limit2) then
in_mandelbrot = .false.
exit
end if
end do
if (in_mandelbrot) then
! Inside the set so set this bit to 1
byte_acc = ior(ishft(byte_acc,1),K1)
else
! Outside the set so set this bit to 0
byte_acc = ishft(byte_acc,1)
end if
bit_num = bit_num + 1
if (bit_num == 8) then
! All bits set so output them
write(*,'(a1)',advance='no') char(byte_acc)
byte_acc = K0
bit_num = 0
elseif (x == w-1) then
! End of a row so left-justify the bits we have and output them
byte_acc = ishft(byte_acc,8-mod(w,8))
write(*,'(a1)',advance='no') char(byte_acc)
byte_acc = K0
bit_num = 0
end if
end do
end do
end program mandelbrot
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