def test_fixed_diff():
a = np.random.randn(2, 3, 4)
da = fixed_diff(a, axis=1, initial_value=0)
assert np.array_equal(da[:, 1:, :], np.diff(a, axis=1))
assert np.array_equal(da[:, 0, :], a[:, 0, :])
da = fixed_diff(a, axis=1, initial_value='first')
assert np.array_equal(da[:, 1:, :], np.diff(a, axis=1))
assert np.array_equal(da[:, 0, :], np.zeros_like(da[:, 0, :]))
assert np.allclose(a, np.cumsum(fixed_diff(a, axis=1), axis=1))
def test_fixed_diff():
a = np.random.randn(2, 3, 4)
da = fixed_diff(a, axis=1, initial_value=0)
assert np.array_equal(da[:, 1:, :], np.diff(a, axis=1))
assert np.array_equal(da[:, 0, :], a[:, 0, :])
da = fixed_diff(a, axis=1, initial_value='first')
assert np.array_equal(da[:, 1:, :], np.diff(a, axis=1))
assert np.array_equal(da[:, 0, :], np.zeros_like(da[:, 0, :]))
assert np.allclose(a, np.cumsum(fixed_diff(a, axis=1), axis=1))
def sequential_quantize(v, n_steps = None, method='herd', rng = None):
"""
:param v: A (..., n_samples, n_units, ) array
:param n_steps: The number of steps to spike for
:return: An (..., n_steps, n_units) array of quantized values
"""
rng = get_rng(rng)
assert v.ndim>=2
if n_steps is None:
n_steps = v.shape[-2]
else:
assert n_steps == v.shape[-2]
if method=='herd':
result = fixed_diff(np.round(np.cumsum(v, axis=-2)), axis=-2)
elif method=='herd2':
result = fixed_diff(fixed_diff(np.round(np.cumsum(np.cumsum(v, axis=-2), axis=-2)), axis=-2), axis=-2)
elif method=='round':
result = np.round(v)
elif method == 'slippery.9':
result = slippery_round(v, slip=0.9)
elif method == 'slippery.5':
result = slippery_round(v, slip=0.5)
elif method == 'randn':
result = v + rng.randn(*v.shape)
elif method=='uniform':
result = v + rng.uniform(-.5, .5, size=v.shape)
elif method=='surrogate-noise':
result = v + (12**.5)*((v%1)-(v%1)**2)*rng.uniform(low=-.5, high=.5, size=v.shape)
elif method == 'surrogate-sqrt':
result = v + np.sqrt((12**.5)*((v%1)-(v%1)**2)*rng.uniform(low=-.5, high=.5, size=v.shape))
elif method is None:
result = v
else:
raise NotImplementedError("Don't have quantization method '%s' implemented" % (method, ))
return result