Ejemplo n.º 1
0
def advanced_indexing(volume, *indices_list, **kwargs):
    """ Performs advanced indexing on `volume`.

    This function exists because in Theano<=0.9 advanced indexing is
    only supported along the first dimension.

    Notes
    -----
    Assuming `volume` is C contiguous.
    """
    strides = kwargs.get("strides")
    if strides is None:
        shapes = T.cast(volume.shape[:len(indices_list)],
                        dtype=theano.config.floatX)
        strides = T.concatenate([T.ones(
            (1, )), T.cumprod(shapes[::-1])[:-1]],
                                axis=0)[::-1]

    shapes = T.cast(volume.shape, dtype=theano.config.floatX)

    indices = T.maximum(
        0, T.minimum(indices_list[-1], shapes[len(indices_list) - 1] - 1))
    for i in range(len(indices_list) - 1):
        clipped_idx = T.maximum(0, T.minimum(indices_list[i], shapes[i] - 1))
        indices += clipped_idx * strides[i]

    # indices = T.sum(T.stack(indices_list, axis=1)*strides[:len(indices_list)], axis=1)
    indices = T.cast(indices, dtype="int32")
    return volume.reshape((-1, volume.shape[-1]))[indices]
Ejemplo n.º 2
0
def test_trilinear_interpolation():
    trk = nib.streamlines.load(
        os.path.abspath(pjoin(__file__, '..', 'data', 'CA.trk')))
    trk.tractogram.apply_affine(np.linalg.inv(trk.affine))

    dwi = nib.load(os.path.abspath(pjoin(__file__, '..', 'data',
                                         'dwi.nii.gz')))
    expected = eval_volume_at_3d_coordinates(dwi.get_data().astype('float32'),
                                             trk.streamlines._data)

    coords = T.matrix("coords")
    coords.tag.test_value = trk.streamlines._data
    volume = T.tensor3("image")
    volume.tag.test_value = dwi.get_data()[..., 0]
    fct = theano.function([volume, coords],
                          eval_volume_at_3d_coordinates_in_theano(
                              volume, coords))
    # theano.printing.pydotprint(fct, 'interpolation_vol3d', with_ids=True)

    # Process directly multiple 3D volumes then concatenate the results.
    values = []
    for i in range(dwi.shape[-1]):
        values_tmp = fct(dwi.get_data()[..., i], trk.streamlines._data)
        values.append(values_tmp)

    values = np.array(values).T
    assert_array_almost_equal(values, expected, decimal=4)

    # Process directly the 4D volume.
    volume = theano.shared(dwi.get_data())
    coords = theano.shared(trk.streamlines._data)

    # Precompute strides that will be used in the interpolation.
    shapes = T.cast(volume.shape[:-1], dtype=theano.config.floatX)
    strides = T.concatenate([T.ones(
        (1, )), T.cumprod(shapes[::-1])[:-1]],
                            axis=0)[::-1]
    volume_strides = strides.eval()

    values = eval_volume_at_3d_coordinates_in_theano(
        volume, coords, strides=volume_strides).eval()
    assert_array_almost_equal(values, expected, decimal=4)

    # fct = theano.function([], eval_volume_at_3d_coordinates_in_theano(volume, coords, strides=volume_strides))
    # theano.printing.pydotprint(fct, 'interpolation_vol4d', with_ids=True)

    # Test tahat coordinates outside the volume are clipped.
    coords = coords * np.max(dwi.shape).astype('float32')
    expected = eval_volume_at_3d_coordinates(dwi.get_data().astype('float32'),
                                             coords.eval())
    values = eval_volume_at_3d_coordinates_in_theano(
        volume, coords, strides=volume_strides).eval()
    assert_array_almost_equal(values, expected, decimal=4)

    coords = -coords
    expected = eval_volume_at_3d_coordinates(dwi.get_data().astype('float32'),
                                             coords.eval())
    values = eval_volume_at_3d_coordinates_in_theano(
        volume, coords, strides=volume_strides).eval()
    assert_array_almost_equal(values, expected, decimal=4)
Ejemplo n.º 3
0
def advanced_indexing(volume, *indices_list, **kwargs):
    """ Performs advanced indexing on `volume`.

    This function exists because in Theano<=0.9 advanced indexing is
    only supported along the first dimension.

    Notes
    -----
    Assuming `volume` is C contiguous.
    """
    strides = kwargs.get("strides")
    if strides is None:
        shapes = T.cast(volume.shape[:len(indices_list)], dtype=theano.config.floatX)
        strides = T.concatenate([T.ones((1,)), T.cumprod(shapes[::-1])[:-1]], axis=0)[::-1]

    shapes = T.cast(volume.shape, dtype=theano.config.floatX)

    indices = T.maximum(0, T.minimum(indices_list[-1], shapes[len(indices_list)-1]-1))
    for i in range(len(indices_list)-1):
        clipped_idx = T.maximum(0, T.minimum(indices_list[i], shapes[i]-1))
        indices += clipped_idx * strides[i]

    # indices = T.sum(T.stack(indices_list, axis=1)*strides[:len(indices_list)], axis=1)
    indices = T.cast(indices, dtype="int32")
    return volume.reshape((-1, volume.shape[-1]))[indices]
Ejemplo n.º 4
0
def sym_pemb(P, order, roughness):
    # embed precision matrix (symbolic operation)
    k = -T.ones(order)
    d = T.arange(order)
    k = k**d
    d = d * 2
    x = roughness * T.sqrt(2)
    r = T.zeros(order)
    r = T.join(0, [T.cumprod(1 - d) / (x**d), np.zeros(order)]).T
    r = r.flatten(1)[:-1]
    R = T.join(0, [r[i:i + order] for i in range(order)])
    R = R * k.reshape((1, order))
    R = T.nlinalg.matrix_inverse(R)
    return T.cast(sym_kron(R, P), theano.config.floatX)
Ejemplo n.º 5
0
def test_trilinear_interpolation():
    trk = nib.streamlines.load(os.path.abspath(pjoin(__file__, '..', 'data', 'CA.trk')))
    trk.tractogram.apply_affine(np.linalg.inv(trk.affine))

    dwi = nib.load(os.path.abspath(pjoin(__file__, '..', 'data', 'dwi.nii.gz')))
    expected = eval_volume_at_3d_coordinates(dwi.get_data().astype('float32'), trk.streamlines._data)

    coords = T.matrix("coords")
    coords.tag.test_value = trk.streamlines._data
    volume = T.tensor3("image")
    volume.tag.test_value = dwi.get_data()[..., 0]
    fct = theano.function([volume, coords], eval_volume_at_3d_coordinates_in_theano(volume, coords))
    # theano.printing.pydotprint(fct, 'interpolation_vol3d', with_ids=True)

    # Process directly multiple 3D volumes then concatenate the results.
    values = []
    for i in range(dwi.shape[-1]):
        values_tmp = fct(dwi.get_data()[..., i], trk.streamlines._data)
        values.append(values_tmp)

    values = np.array(values).T
    assert_array_almost_equal(values, expected, decimal=4)

    # Process directly the 4D volume.
    volume = theano.shared(dwi.get_data())
    coords = theano.shared(trk.streamlines._data)

    # Precompute strides that will be used in the interpolation.
    shapes = T.cast(volume.shape[:-1], dtype=theano.config.floatX)
    strides = T.concatenate([T.ones((1,)), T.cumprod(shapes[::-1])[:-1]], axis=0)[::-1]
    volume_strides = strides.eval()

    values = eval_volume_at_3d_coordinates_in_theano(volume, coords, strides=volume_strides).eval()
    assert_array_almost_equal(values, expected, decimal=4)

    # fct = theano.function([], eval_volume_at_3d_coordinates_in_theano(volume, coords, strides=volume_strides))
    # theano.printing.pydotprint(fct, 'interpolation_vol4d', with_ids=True)

    # Test tahat coordinates outside the volume are clipped.
    coords = coords * np.max(dwi.shape).astype('float32')
    expected = eval_volume_at_3d_coordinates(dwi.get_data().astype('float32'), coords.eval())
    values = eval_volume_at_3d_coordinates_in_theano(volume, coords, strides=volume_strides).eval()
    assert_array_almost_equal(values, expected, decimal=4)

    coords = -coords
    expected = eval_volume_at_3d_coordinates(dwi.get_data().astype('float32'), coords.eval())
    values = eval_volume_at_3d_coordinates_in_theano(volume, coords, strides=volume_strides).eval()
    assert_array_almost_equal(values, expected, decimal=4)
Ejemplo n.º 6
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    def _initialize_reps(self):
        self._reps = {}

        if self.nonparametric:
            # nu_aux = np.array([2.]+[-1.]*(self.nlatfeats-1))
            nu_aux = np.array([0.]*self.nlatfeats)

            self._reps['nu'] = shared(nu_aux, name='nu')

            self._nu = T.nnet.sigmoid(self._reps['nu'])
            self._mu = T.cumprod(self._nu)
        
        verbreps_aux = np.random.normal(0., 1e-2, size=[self.data.n('verb')-self.data.n('clausetype'),
                                                         self.nlatfeats])
        projection_aux = np.random.normal(0., 1e-2, size=[self.nlatfeats, self.data.n('feature')])
        verbfeatprob_aux = np.zeros([self.data.n('verb')-self.data.n('clausetype'), self.nlatfeats])-4.

        if self.data.n('clausetype'):
            try:
                assert self.data.n('clausetype') <= self.nlatfeats
            except AssertionError:
                raise ValueError('nlatfeats must be greater than or equal to the number of clausetypes')
            
            ctype_ident = (1.-1e-10)*np.eye(self.data.n('clausetype'))
            ct_aux_vr = np.log(ctype_ident)-np.log(1.-ctype_ident)

            ct_aux_vr = np.concatenate([ct_aux_vr, -np.inf*np.ones([self.data.n('clausetype'),
                                                                    self.nlatfeats-self.data.n('clausetype')])],
                                       axis=1)

            ct_aux_vfp = np.inf*np.ones([self.data.n('clausetype'), self.nlatfeats])


            verbreps_aux = np.concatenate([ct_aux_vr, verbreps_aux])
            verbfeatprob_aux = np.concatenate([ct_aux_vfp, verbfeatprob_aux])
            
        self._reps['verbreps'] = shared(verbreps_aux, name='verbreps')
        self._reps['projection'] = shared(projection_aux, name='projection')        
        self._reps['verbfeatprob'] = shared(verbfeatprob_aux, name='verbfeatprob')

        self._verbreps = T.nnet.sigmoid(self._reps['verbreps'])
        self._projection = T.nnet.sigmoid(self._reps['projection'])
        self._verbfeatprob = T.nnet.sigmoid(self._reps['verbfeatprob'])
        
        softand = self._verbfeatprob[:,:,None]*self._verbreps[:,:,None]*self._projection[None,:,:]
        self._featureprob = 1.-T.prod(1.-softand, axis=1)
Ejemplo n.º 7
0
    def step(x_t, y_t, o_tm1, A, B, dodA, dodB, dodotm1):
        # the model itself
        o_t = T.dot(x_t, A) + T.dot(o_tm1, B)
        mse = T.mean(T.sum(T.square(y_t - o_t), axis=0))

        # gradient of o_t w.r.t. A is x_t, w.r.t. B is o_tm1, w.r.t. o_tm1 is B
        dodA_t = T.repeat(T.shape_padright(T.mean(x_t, axis=0)),
                          repeats=n_out,
                          axis=1)
        dodA_up = T.concatenate([T.shape_padleft(dodA_t), dodA[:-1]], axis=0)
        dodB_t = T.repeat(T.shape_padright(T.mean(o_tm1, axis=0)),
                          repeats=n_out,
                          axis=1)
        dodB_up = T.concatenate([T.shape_padleft(dodB_t), dodB[:-1]], axis=0)
        dodotm1_t = B
        dodotm1_up = T.concatenate([T.shape_padleft(dodotm1_t), dodotm1[:-1]],
                                   axis=0)

        # deltaE:   update component from current error
        #           take mean over batch index
        #           and padleft so size is 1 x n_out
        deltaE = T.shape_padleft(T.mean(T.grad(mse, o_t),
                                        axis=0))  # mean over the batch index

        # deltaR:   update components over time from recurrence
        #           cumulative product effectively does backprop
        #           size is bptt_limit x n_out x n_out
        deltaR = T.cumprod(dodotm1_up, axis=0)

        # updates
        #        dA = T.dot(deltaE,T.sum(T.batched_dot(deltaR,dodA_up),axis=0))
        dA = deltaE * T.sum(T.batched_dot(deltaR, dodA_up), axis=0)
        dB = deltaE * T.sum(T.batched_dot(deltaR, dodB_up), axis=0)

        updates = OrderedDict()
        updates[A] = A - learning_rate * dA
        updates[B] = B - learning_rate * dB
        updates[dodA] = dodA_up
        updates[dodB] = dodB_up
        updates[dodotm1] = dodotm1_up
        return [o_t, mse, dA], updates