diff --git a/__init__.py b/__init__.py
index 0f057a6..127df37 100644
--- a/__init__.py
+++ b/__init__.py
@@ -1,2 +1,2 @@
-from frst import sfs_tools, customgraphics, vcf_utils, sfs_tools, stats_sfs, dependences
+from frst import sfs_tools, customgraphics, vcf_utils, sfs_tools, stats_sfs, dependences, swp2
 
diff --git a/sfs_tools.py b/sfs_tools.py
index 22d576e..f08caa3 100755
--- a/sfs_tools.py
+++ b/sfs_tools.py
@@ -227,11 +227,23 @@ def barplot_sfs(sfs,  xlab, ylab, folded=True, title = "Barplot", transformed =
         sum_val = sum(sfs_val)
         for k, sfs_bin in enumerate(sfs_val):
             sfs_val[k] = sfs_bin / sum_val
+        #print(sum(sfs_val))
     #build the plot
     title = title+" (n="+str(len(sfs_val)+1)+") [folded="+str(folded)+"]"+" [transformed="+str(transformed)+"]"
     print("SFS =", sfs)
+    if folded:
+        xlab = "Minor allele frequency"
     if transformed:
         print("Transformed SFS ( n =",len(sfs_val)+1, ") :", sfs_val)
+        plt.axhline(y=1/n, color='r', linestyle='-')
+    else:
+        if normalized:
+            # then plot a theoritical distribution as 1/i
+            expected_y = [1/(2*x+1) for x in list(sfs.keys())]
+            print(sum(expected_y))
+            plt.plot([x for x in list(sfs.keys())], expected_y, color='r', linestyle='-')
+            #print(expected_y)
+            
     customgraphics.barplot(x = [x for x in list(sfs.keys())], y= sfs_val, xlab = xlab, ylab = ylab, title = title)
     plt.show()