def time_delay_generator(x, y, delays, batch_size, weights=None, shuffle=True):
'''A generator to make it easy to fit time-delay regression models,
i.e. a model where the value of y depends on past values of x
# Arguments
x: input data, as a Numpy array
y: targets, as a Numpy array or None for prediction generation
delays: number of time-steps to include in model
weights: Numpy array of weights for the samples
shuffle: Whether or not to shuffle the data (set True for training)
# Example
if X_train is (1000,200), Y_train is (1000,1)
train_gen = time_delay_generator(X_train, Y_train, delays=10, batch_size=100)
train_gen is a generator that gives:
x_batch as size (100,10,200) since each of the 100 samples includes the input
data at the current and nine previous time steps
y_batch as size (100,1)
w_batch as size (100,)
'''
if type(delays) is int:
delays = range(delays)
if type(x) is not list:
x = list([x])
index_array = np.arange(x[0].shape[0])
tlists = [[1, 0] + list(range(2, np.ndim(xx) + 1)) for xx in x]
batches = _make_batches(x[0].shape[0], batch_size)
while 1:
if shuffle:
np.random.shuffle(index_array)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
batch_ids_delay = [
np.minimum(np.maximum(0, batch_ids - d), x[0].shape[0] - 1)
for d in delays
]
x_batch = _standardize_input_data([
xx[batch_ids_delay, :].transpose(tt)
for xx, tt in zip(x, tlists)
], ['x_batch' + str(i) for i in range(1,
len(x) + 1)])
if y is None:
yield x_batch
else:
y_batch = _standardize_input_data(y[batch_ids, :], ['y_batch'])
if weights is not None:
w_batch = weights[batch_ids, :][:, 0]
else:
w_batch = np.ones(x_batch[0].shape[0])
w_batch[batch_ids < delays[-1]] = 0.
w_batch = _standardize_sample_weights(w_batch, ['w_batch'])
yield (x_batch, y_batch, w_batch)
def _standardize_user_data(model,
x,
y,
sample_weight=None,
class_weight=None,
check_batch_dim=True,
batch_size=None):
if not hasattr(model, 'optimizer'):
raise Exception('You must compile a model before training/testing.'
' Use `model.compile(optimizer, loss)`.')
output_shapes = []
for output_shape, loss_fn in zip(model.internal_output_shapes,
model.loss_functions):
if loss_fn.__name__ == 'sparse_categorical_crossentropy':
output_shapes.append(output_shape[:-1] + (1, ))
elif getattr(losses, loss_fn.__name__, None) is None:
output_shapes.append(None)
else:
output_shapes.append(output_shape)
x = _standardize_input_data(x,
model.input_names,
model.internal_input_shapes,
exception_prefix='model input')
y = _standardize_input_data(y,
model.output_names,
output_shapes,
exception_prefix='model target')
sample_weights = _standardize_sample_weights(sample_weight,
model.output_names)
class_weights = _standardize_class_weights(class_weight,
model.output_names)
sample_weights = [
_standardize_weights(ref, sw, cw, mode) for (ref, sw, cw, mode) in zip(
y, sample_weights, class_weights, model.sample_weight_modes)
]
'''
We only need to comment out check_array_lengeh(x, y, weights) in the next line to
let the model compile and train.
'''
# check_array_lengths(x, y, sample_weights)
_check_loss_and_target_compatibility(y, model.loss_functions,
model.internal_output_shapes)
if model.stateful and batch_size:
if x[0].shape[0] % batch_size != 0:
raise Exception('In a stateful network, '
'you should only pass inputs with '
'a number of samples that can be '
'divided by the batch size. Found: ' +
str(x[0].shape[0]) + ' samples')
return x, y, sample_weights
def time_delay_generator_jitter(x, y, delays, batch_size, weights=None, shuffle=True, conv3d=False, jitter=True, jitter_axes=[3,4], max_jitter=1):
'''A generator to make it easy to fit time-delay regression models,
i.e. a model where the value of y depends on past values of x
# Arguments
x: input data, as a Numpy array
y: targets, as a Numpy array or None for prediction generation
delays: number of time-steps to include in model
weights: Numpy array of weights for the samples
shuffle: Whether or not to shuffle the data (set True for training)
# Example
if X_train is (1000,200), Y_train is (1000,1)
train_gen = time_delay_generator(X_train, Y_train, delays=10, batch_size=100)
train_gen is a generator that gives:
x_batch as size (100,10,200) since each of the 100 samples includes the input
data at the current and nine previous time steps
y_batch as size (100,1)
w_batch as size (100,)
'''
index_array = np.arange(x.shape[0])
if conv3d:
tlist = [1, 2, 0] + range(3, np.ndim(x) + 1)
else:
tlist = [1, 0] + range(2, np.ndim(x) + 1)
batches = _make_batches(x.shape[0], batch_size)
while 1:
if shuffle:
np.random.shuffle(index_array)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
batch_ids = [np.maximum(0, batch_ids - d) for d in range(delays)]
x_batch = x[batch_ids, :].transpose(tlist)
if jitter:
for j in jitter_axes:
x_batch = np.roll(x_batch, np.random.randint(-max_jitter,max_jitter+1), axis=j)
x_batch = _standardize_input_data(x_batch, ['x_batch'])
if y is None:
yield x_batch
else:
y_batch = _standardize_input_data(y[batch_ids[0], :], ['y_batch'])
if weights is not None:
w_batch = weights[batch_ids[0], :][:, 0]
else:
w_batch = np.ones(x_batch[0].shape[0])
w_batch[batch_ids[0] < delays] = 0.
w_batch = _standardize_sample_weights(w_batch, ['w_batch'])
yield (x_batch, y_batch, w_batch)
def keras_generator(self, delays=7, batch_size=400, cell=0, scale=5, flatten=True, center=None, crop_size=None, shuffle=True, color_chan=False, log_transform_events=True, correct_eye_pos=False, gaussian_filter=0):
from keras.engine.training import _standardize_input_data, _make_batches, _standardize_sample_weights
if type(cell) is int:
cell = [cell]
if type(delays) is int:
delays = range(delays)
(stim, events, frame_numbers, weights, shifts) = self.vectorize_data(delays)
evidx = np.where(events)[0]
print(str(len(frame_numbers)) + ' Samples')
print(str(len(evidx)) + ' Events')
if correct_eye_pos:
sh = stim.shape
shift_stim_shape = (len(shifts),
sh[1] + 2*np.maximum(self.min_max_shift[1][0], -self.min_max_shift[0][0]) + 3,
sh[2] + 2*np.maximum(self.min_max_shift[1][1], -self.min_max_shift[0][1]) + 3)
out_stim = np.zeros(shift_stim_shape, dtype='float32')
shifts = shifts + [shift_stim_shape[1]/2, shift_stim_shape[2]/2]
good_shift_locations = ~np.isnan(shifts[:, 0])
for dd in delays:
weights[np.minimum(np.where(np.isnan(shifts[:,0]))[0] + dd, len(weights)-1)] = 0
for i in range(len(shifts)):
if good_shift_locations[i]:
# print(-sh[1]/2 + np.int32(shifts[i, 0]))
# print(np.int32(shifts[i, 0]) + sh[1]/2)
out_stim[i, -sh[1]/2 + np.int32(shifts[i, 0]):np.int32(shifts[i, 0]) + sh[1]/2,
-sh[2]/2 + np.int32(shifts[i, 1]):np.int32(shifts[i, 1]) + sh[2]/2] = stim[frame_numbers[i]]
stim = out_stim
frame_numbers_i = np.arange(len(frame_numbers))
else:
frame_numbers_i = frame_numbers
if color_chan:
stim = stim[:, None, :, :]
if crop_size is not None and center is not None:
crop_range = np.arange(-crop_size/2, crop_size/2)
stim = stim[:, (center[0]-crop_size/2):(center[0]+crop_size/2), (center[1]-crop_size/2):(center[1]+crop_size/2)]
if flatten:
stim = stim.reshape(stim.shape[0], -1)
events = np.asarray(events)
events = events[cell].T * scale
if log_transform_events:
events = np.log(1 + events)
if gaussian_filter > 0:
events = gaussian_filter1d(events, gaussian_filter)
index_array = np.arange(events.shape[0])
tlist = [1, 0] + list(range(2, np.ndim(stim) + 1))
batches = _make_batches(events.shape[0], batch_size)
while 1:
if shuffle:
np.random.shuffle(index_array)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
frame_numbers_b = frame_numbers[batch_ids]
batch_ids_stim = [frame_numbers_i[np.maximum(0, batch_ids - d)] for d in delays]
x_batch = _standardize_input_data(stim[batch_ids_stim, :].transpose(tlist), ['x_batch'])
y_batch = _standardize_input_data(events[batch_ids, :], ['y_batch'])
w_batch = weights[batch_ids]
w_batch[frame_numbers_b < delays[-1]] = 0.
w_batch = _standardize_sample_weights(w_batch, ['w_batch'])
yield (x_batch, y_batch, w_batch)
