def plotcdf(x,xmin,alpha):
    """
    Plots CDF and powerlaw
    """

    x=sort(x)
    n=len(x)
    xcdf = arange(n,0,-1,dtype='float')/float(n)

    q = x[x>=xmin]
    fcdf = (q/xmin)**(1-alpha)
    nc = xcdf[argmax(x>=xmin)]
    fcdf_norm = nc*fcdf

    loglog(x,xcdf)
    loglog(q,fcdf_norm)