code: def strakos(n, l_min=0.1, l_max=100, rho=0.9):
      
      d = [l_min + (i-1)*1./(n-1)*(l_max-l_min)*(rho**(n-i))
           for i in range(1, n+1)]
      return numpy.diag(d)
docs: Return the Strakoš matrix.
  
      See [Str92]_.