source: interfaces/python/test_fft.py @ 4435ea6e

from numpy.testing import TestCase, run_module_suite
from numpy.testing import assert_equal, assert_almost_equal
# WARNING: numpy also has an fft object
from aubio import fvec, fft, cvec
from numpy import array, shape
from math import pi

class aubio_fft_test_case(TestCase):

  def test_members(self):
    f = fft()
    assert_equal (f.win_s, 1024)

  def test_output_dimensions(self):
    """ check the dimensions of output """
    win_s = 1024
    timegrain = fvec(win_s)
    f = fft(win_s)
    fftgrain = f (timegrain)
    assert_equal (fftgrain.norm, 0)
    assert_equal (shape(fftgrain.norm), (win_s/2+1,))
    assert_equal (fftgrain.phas, 0)
    assert_equal (shape(fftgrain.phas), (win_s/2+1,))

  def test_zeros(self):
    """ check the transform of zeros """
    win_s = 512
    timegrain = fvec(win_s)
    f = fft(win_s)
    fftgrain = f(timegrain)
    assert_equal ( fftgrain.norm == 0, True )
    assert_equal ( fftgrain.phas == 0, True )

  def test_impulse(self):
    """ check the transform of one impulse at a random place """
    from random import random
    from math import floor
    win_s = 256
    i = floor(random()*win_s)
    impulse = pi * random() 
    f = fft(win_s)
    timegrain = fvec(win_s)
    timegrain[i] = impulse 
    fftgrain = f ( timegrain )
    #self.plot_this ( fftgrain.phas )
    assert_almost_equal ( fftgrain.norm, impulse, decimal = 6 )
    assert_equal ( fftgrain.phas <= pi, True)
    assert_equal ( fftgrain.phas >= -pi, True)

  def test_impulse_negative(self):
    """ check the transform of one impulse at a random place """
    from random import random
    from math import floor
    win_s = 256
    i = 0 
    impulse = -10. 
    f = fft(win_s)
    timegrain = fvec(win_s)
    timegrain[i] = impulse 
    fftgrain = f ( timegrain )
    #self.plot_this ( fftgrain.phas )
    assert_almost_equal ( fftgrain.norm, abs(impulse), decimal = 6 )
    if impulse < 0:
      # phase can be pi or -pi, as it is not unwrapped
      assert_almost_equal ( abs(fftgrain.phas[1:-1]) , pi, decimal = 6 )
      assert_almost_equal ( fftgrain.phas[0], pi, decimal = 6)
      assert_almost_equal ( fftgrain.phas[-1], pi, decimal = 6)
    else:
      assert_equal ( fftgrain.phas[1:-1] == 0, True)
      assert_equal ( fftgrain.phas[0] == 0, True)
      assert_equal ( fftgrain.phas[-1] == 0, True)
    # now check the resynthesis
    synthgrain = f.rdo ( fftgrain )
    #self.plot_this ( fftgrain.phas.T )
    assert_equal ( fftgrain.phas <= pi, True)
    assert_equal ( fftgrain.phas >= -pi, True)
    #self.plot_this ( synthgrain - timegrain )
    assert_almost_equal ( synthgrain, timegrain, decimal = 6 )

  def test_impulse_at_zero(self):
    """ check the transform of one impulse at a index 0 """
    win_s = 1024
    impulse = pi
    f = fft(win_s)
    timegrain = fvec(win_s)
    timegrain[0] = impulse 
    fftgrain = f ( timegrain )
    #self.plot_this ( fftgrain.phas )
    assert_equal ( fftgrain.phas[0], 0)
    assert_equal ( fftgrain.phas[1], 0)
    assert_almost_equal (fftgrain.norm[0], impulse, decimal = 6 )

  def test_rdo_before_do(self):
    """ check running fft.rdo before fft.do works """
    win_s = 1024
    impulse = pi
    f = fft(win_s)
    fftgrain = cvec(win_s)
    t = f.rdo( fftgrain )
    assert_equal ( t, 0 )

  def plot_this(self, this):
    from pylab import plot, show
    plot ( this )
    show ()

if __name__ == '__main__':
  from unittest import main
  main()