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program code426
parameter (MZ=26) !Number of 4-FSK symbols
parameter (JZMAX=64) !Desired number of codewords
integer ic(MZ,JZMAX),icsave(MZ)
real c(MZ)
character*12 arg
nargs=iargc()
if(nargs.ne.2) then
print*,'Usage: code426 <nmsgs> <iters>'
print*,'Example: code426 64 10000000'
go to 999
endif
call getarg(1,arg)
read(arg,*) nmsgs
call getarg(2,arg)
read(arg,*) iters
call init_random_seed()
open(13,file='code426.out',status='unknown')
write(*,1002) nmsgs,iters
write(13,1002) nmsgs,iters
1002 format('Nmsgs:',i4,' Iters:',i10/(66('-')))
do i=1,MZ !Create 4 mutually orthogonal codewords
ic(i,1)=mod(i-1,4)
ic(i,2)=mod(i,4)
ic(i,3)=mod(i+1,4)
ic(i,4)=mod(i+2,4)
enddo
do j=1,4 !Write them out
write(*,1000) j,MZ,ic(1:MZ,j)
write(13,1000) j,MZ,ic(1:MZ,j)
1000 format(2i5,3x,26i2)
enddo
do j=5,nmsgs !Find codewords up to j=nmsgs with maximum
npk=0 !distance from all the rest
do i=1,iters
call random_number(c) !Generate a random codeword candidate
ic(1:MZ,j)=int(4*c) !Convert real to integer
! nd=MZ
! do k=1,j-1 !Test candidate against all others in list
! n=count(ic(1:MZ,j).ne.ic(1:MZ,k))
! nd=min(n,nd)
! enddo
call dist426(ic,j,mind)
if(mind.gt.npk) then
npk=mind
icsave=ic(1:MZ,j) !Best candidate so far, save it
! if(npk.ge.19) exit !It won't get any better...
endif
enddo
write(*,1000) j,npk,ic(1:MZ,j)
write(13,1000) j,npk,ic(1:MZ,j)
enddo
999 end program code426
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