program bifurcation implicit none real r,x_ini,x,xi integer pgopen,i,i_again,isymbol,n_gen,j,n_group_size isymbol = -1 write (*,*) 'This plots fix-points x* of x_n+1=4rx_n(1-x_n+1).' write (*,*) c write (*,*) 'What is the initial value of x (0 < x < 1) ?' c read (*,*) x_ini x_ini = 0.5 if ( pgopen('/xwin') .le. 0 ) stop c call pgpap(5.0,0.75) 100 write (*,*) 'What is the numer of generation for the mapping ?' read (*,*) n_gen call pgeras call pgsci(1) call pgenv(0.0, 1.0, 0.0, 1.0, 0, 0) call pglab('r','x','x\u*') n_ group_size = n_gen/15 do j=1,1000 r = j/1000.0 x = x_ini do i=1,n_gen x = 4*r*x*(1-x) call pgsci(i/n_group_size) c if (i.gt.(0.1*n_gen)) call pgpt(1,r,x,isymbol) call pgpt(1,r,x,isymbol) end do end do 102 write (*,*) 'Again ? (1=YES;0=NO)' read (*,*) i_again if (i_again.eq.1) goto 100 if (i_again.eq.0) stop goto 102 end