Important: To compute anything on real axis one has to obtain mu0 and doping values from IPT program on matsubara axis. Real axis program is mostly serves as a way to make analytical continuation to the real axis. The output from IPT on matsubara axis is two column file "dop_mu0t.in":

        mu0     doping

for a range of mu values and a given U. It is used as the second input file in the directory with real axis program to compute Green's function.
 

"input.dat" structure:(see below an example)

1. the parameter U must match with that used in Step 0.
2. choose range of temperatures
3. the range of doping values must lie within the one of the file "dop_mu0t.in" (second column).
4. number of lines of the file "dop_mu0t.in"
5. t: hopping parameter; nloop: maximum number of iterations (main loops)
6. eta is the artificial broadening (to get the program to converge), tomega: used in the subroutine "init" to construct the real frequency grid: tomega is the length of the real frequency interval.
7. acc: sets the accuracy for the spectral function; accy, accmu: for finite temperatures, the chemical potential mu has to be recalculated. In this context, the root of a function y=f(deltamu) has to be found. The ever decreasing interval length must shrink to below accmu or the function at the boundaries must become smaller than accy.
8. for the output Green's function, one does not need as many points and as high the ultraviolet cutoff in the Fourier transforms. With wmin, wmax, stepsi, one can choose the minimum and maximum integer indices to make printout.
9. ommax -- maximum omega range to printout, stepm -- step in matsubara frequency
10. inguess -- probe function to start simulations 1- metal like, 2- insulating one; average -- smoothing parameter
11. print_test -- to make test printouts;  matout -- to make matsubara GF printout
12. imse_mode -- to make the self energy printouts;

u0min,  u0max,  u0step
Tmin,   Tmax,   Tstep
dopmin, dopmax, dopstep
nmu0t   number of data points in dop_mu0t.dat)
t,      nloop
eta,    tomega (80)
acc,    accy,   accmu
wmin,   wmax,   stepsi
ommax   (20, 1d30 gives whole range),stepm
inguess (1=metal, 2=insulator), average (0-10)
print_test (1:on, 0:off), matout
imse_mode (1:on, 0:off)