source: interfaces/python/test_fft.py @ 0536612

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 fft, fvec, 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, f.channels], [1024, 1])
    f = fft(2048, 4)
    assert_equal ([f.win_s, f.channels], [2048, 4])

  def test_output_dimensions(self):
    """ check the dimensions of output """
    win_s, chan = 1024, 3
    timegrain = fvec(win_s, chan)
    f = fft(win_s, chan)
    fftgrain = f (timegrain)
    assert_equal (array(fftgrain), 0)
    assert_equal (shape(fftgrain), (chan * 2, win_s/2+1))
    assert_equal (fftgrain.norm, 0)
    assert_equal (shape(fftgrain.norm), (chan, win_s/2+1))
    assert_equal (fftgrain.phas, 0)
    assert_equal (shape(fftgrain.phas), (chan, win_s/2+1))

  def test_zeros(self):
    """ check the transform of zeros """
    win_s, chan = 512, 3
    timegrain = fvec(win_s, chan)
    f = fft(win_s, chan)
    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, chan = 256, 1
    i = floor(random()*win_s)
    impulse = pi * random() 
    f = fft(win_s, chan)
    timegrain = fvec(win_s, chan)
    timegrain[0][i] = impulse 
    fftgrain = f ( timegrain )
    #self.plot_this ( fftgrain.phas[0] )
    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, chan = 256, 1
    i = 0 
    impulse = -10. 
    f = fft(win_s, chan)
    timegrain = fvec(win_s, chan)
    timegrain[0][i] = impulse 
    fftgrain = f ( timegrain )
    #self.plot_this ( fftgrain.phas[0] )
    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[0][1:-1]) , pi, decimal = 6 )
      assert_almost_equal ( fftgrain.phas[0][0], pi, decimal = 6)
      assert_almost_equal ( fftgrain.phas[0][-1], pi, decimal = 6)
    else:
      assert_equal ( fftgrain.phas[0][1:-1] == 0, True)
      assert_equal ( fftgrain.phas[0][0] == 0, True)
      assert_equal ( fftgrain.phas[0][-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 in one channel """
    win_s, chan = 1024, 2
    impulse = pi
    f = fft(win_s, chan)
    timegrain = fvec(win_s, chan)
    timegrain[0][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 )
    assert_equal ( fftgrain.norm[0], impulse)

  def test_rdo_before_do(self):
    """ check running fft.rdo before fft.do works """
    win_s, chan = 1024, 2
    impulse = pi
    f = fft(win_s, chan)
    fftgrain = cvec(win_s, chan)
    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()