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 ' print*,'Example: code426 64 10000000' go to 999 endif call getarg(1,arg) read(arg,*) nmsgs call getarg(2,arg) read(arg,*) iters 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) ic(1:MZ,j)=int(4*c) nd=MZ do k=1,j-1 !Test candidate against all others in list nd=min(nd,count(ic(1:MZ,j).ne.ic(1:MZ,k))) enddo if(nd.gt.npk) then npk=nd icsave=ic(1:MZ,j) !Best candidate so far, save it endif enddo write(*,1000) j,npk,ic(1:MZ,j) write(13,1000) j,npk,ic(1:MZ,j) enddo 999 end program code426