def t60_fitzroy(surfaces, alpha, volume, c=SOUNDSPEED):
"""
Reverberation time according to Fitzroy.
:param surfaces: Surfaces :math:`S`.
:param alpha: Mean absorption coefficient :math:`\\alpha` or by frequency bands
:param volume: Volume of the room :math:`V`.
:param c: Speed of sound :math:`c`.
:returns: Reverberation time :math:`T_{60}`
"""
Sx = np.sum(surfaces[0:2])
Sy = np.sum(surfaces[2:4])
Sz = np.sum(surfaces[4:6])
St = np.sum(surfaces)
alpha = _is_1d(alpha)
a_x = np.average(alpha[:, 0:2], weights=surfaces[0:2], axis=1)
a_y = np.average(alpha[:, 2:4], weights=surfaces[2:4], axis=1)
a_z = np.average(alpha[:, 4:6], weights=surfaces[4:6], axis=1)
factor = -(Sx / np.log(1.0 - a_x) + Sy / np.log(1.0 - a_y) + Sz / np.log(1 - a_z))
t60 = 4.0 * np.log(10.0**6.0) * volume * factor / (c * St**2.0)
return t60
def t60_fitzroy(surfaces, alpha, volume, c=SOUNDSPEED):
"""
Reverberation time according to Fitzroy.
:param surfaces: Surfaces :math:`S`.
:param alpha: Mean absorption coefficient :math:`\\alpha` or by frequency bands
:param volume: Volume of the room :math:`V`.
:param c: Speed of sound :math:`c`.
:returns: Reverberation time :math:`T_{60}`
"""
Sx = np.sum(surfaces[0:2])
Sy = np.sum(surfaces[2:4])
Sz = np.sum(surfaces[4:6])
St = np.sum(surfaces)
alpha = _is_1d(alpha)
a_x = np.average(alpha[:, 0:2], weights=surfaces[0:2], axis=1)
a_y = np.average(alpha[:, 2:4], weights=surfaces[2:4], axis=1)
a_z = np.average(alpha[:, 4:6], weights=surfaces[4:6], axis=1)
factor = -(Sx / np.log(1.0-a_x) + Sy / np.log(1.0-a_y) + Sz / np.log(1-a_z))
t60 = 4.0 * np.log(10.0**6.0) * volume * factor / (c * St**2.0)
return t60
def test__is1d_vector_2darray():
a = np.array([[0.1, 0.2, 0.3]])
is_vector_2darray = _is_1d(a)
a_return = np.array([0.1, 0.2, 0.3])
assert_array_equal(a_return, is_vector_2darray)
def test__is_1d_2darray():
a = np.array([[0.1, 0.2, 0.3], [0.4, 0.5, 0.6]])
is_2d_array = _is_1d(a)
assert_array_equal(a, is_2d_array)
def test__is_1d_1darray():
a = np.array([0.1, 0.2, 0.3])
is_1d_array = _is_1d(a)
a_return = np.array([a])
assert_array_equal(a_return, is_1d_array)
def test__is_1d_float():
a = 0.9
is_float = _is_1d(a)
assert a == is_float
def test__is1d_vector_2darray():
a = np.array([[0.1, 0.2, 0.3]])
is_vector_2darray = _is_1d(a)
a_return = np.array([0.1, 0.2, 0.3])
assert_array_equal(a_return, is_vector_2darray)
def test__is_1d_2darray():
a = np.array([[0.1, 0.2, 0.3], [0.4, 0.5, 0.6]])
is_2d_array = _is_1d(a)
assert_array_equal(a, is_2d_array)
def test__is_1d_1darray():
a = np.array([0.1, 0.2, 0.3])
is_1d_array = _is_1d(a)
a_return = np.array([a])
assert_array_equal(a_return, is_1d_array)
def test__is_1d_float():
a = 0.9
is_float = _is_1d(a)
assert a == is_float