old_contents: from matplotlib import pyplot
  import numpy
  from matplotlib.tri import Triangulation
  from . import compute
  
  
  def visualize(A, 
                real_min=-1, real_max=1, real_n=50,
                imag_min=-1, imag_max=1, imag_n=50,
                levels=None
                ):
      real = numpy.linspace(real_min, real_max, real_n)
      imag = numpy.linspace(imag_min, imag_max, real_n)
  
      x, y = numpy.meshgrid(real, imag)
      x = x.flatten()
      y = y.flatten()
  
      vals = compute.evaluate_points(A, x+1j*y)
  
      triang = Triangulation(x, y)
      pyplot.tricontour(triang, vals, levels=levels)
  
      pyplot.show()
  
  
  
new_contents: from matplotlib import pyplot
  import numpy
  from matplotlib.tri import Triangulation
  from . import compute
  
  
  def visualize(A, 
                real_min=-1, real_max=1, real_n=50,
                imag_min=-1, imag_max=1, imag_n=50,
                levels=None
                ):
      real = numpy.linspace(real_min, real_max, real_n)
      imag = numpy.linspace(imag_min, imag_max, imag_n)
  
      x, y = numpy.meshgrid(real, imag)
      x = x.flatten()
      y = y.flatten()
  
      vals = compute.evaluate_points(A, x+1j*y)
  
      triang = Triangulation(x, y)
      pyplot.tricontour(triang, vals, levels=levels)
      pyplot.colorbar()
  
      pyplot.show()
  
  
  
subject: fix real_n