def calc_grad_z(model, train_loader, save_pth=False, gpu=-1, start=0):
"""Calculates grad_z and can save the output to files. One grad_z should
be computed for each training data sample.
Arguments:
model: pytorch model, for which s_test should be calculated
train_loader: pytorch dataloader, which can load the train data
save_pth: Path, path where to save the grad_z files if desired.
Omitting this argument will skip saving
gpu: int, device id to use for GPU, -1 for CPU (default)
start: int, index of the first test index to use. default is 0
Returns:
grad_zs: list of torch tensors, contains the grad_z tensors
save_pth: Path, path where grad_z files were saved to or
False if they were not saved."""
if save_pth and isinstance(save_pth, str):
save_pth = Path(save_pth)
if not save_pth:
logging.info("ATTENTION: Not saving grad_z files!")
grad_zs = []
for i in tqdm(range(start, len(train_loader.dataset)), desc="Calc. grad_z"):
z, t = train_loader.dataset[i]
z = train_loader.collate_fn([z])
t = train_loader.collate_fn([t])
grad_z_vec = grad_z(z, t, model, gpu=gpu)
if save_pth:
grad_z_vec = [g.cpu() for g in grad_z_vec]
torch.save(grad_z_vec, save_pth.joinpath(f"{i}.grad_z"))
else:
grad_zs.append(grad_z_vec)
return grad_zs, save_pth
def calc_influence_single(model,
train_loader,
test_loader,
test_id_num,
gpu,
recursion_depth,
r,
s_test_vec=None,
time_logging=False):
"""Calculates the influences of all training data points on a single
test dataset image.
Arugments:
model: pytorch model
train_loader: DataLoader, loads the training dataset
test_loader: DataLoader, loads the test dataset
test_id_num: int, id of the test sample for which to calculate the
influence function
gpu: int, identifies the gpu id, -1 for cpu
recursion_depth: int, number of recursions to perform during s_test
calculation, increases accuracy. r*recursion_depth should equal the
training dataset size.
r: int, number of iterations of which to take the avg.
of the h_estimate calculation; r*recursion_depth should equal the
training dataset size.
s_test_vec: list of torch tensor, contains s_test vectors. If left
empty it will also be calculated
Returns:
influence: list of float, influences of all training data samples
for one test sample
harmful: list of float, influences sorted by harmfulness
helpful: list of float, influences sorted by helpfulness
test_id_num: int, the number of the test dataset point
the influence was calculated for"""
# Calculate s_test vectors if not provided
if not s_test_vec:
z_test, t_test = test_loader.dataset[test_id_num]
z_test = test_loader.collate_fn([z_test])
t_test = test_loader.collate_fn([t_test])
s_test_vec = calc_s_test_single(model,
z_test,
t_test,
train_loader,
gpu,
recursion_depth=recursion_depth,
r=r)
# Calculate the influence function
train_dataset_size = len(train_loader.dataset)
influences = []
for i in range(train_dataset_size):
z, t = train_loader.dataset[i]
z = train_loader.collate_fn([z])
t = train_loader.collate_fn([t])
if time_logging:
time_a = datetime.datetime.now()
grad_z_vec = grad_z(z, t, model, gpu=gpu)
if time_logging:
time_b = datetime.datetime.now()
time_delta = time_b - time_a
logging.info(f"Time for grad_z iter:"
f" {time_delta.total_seconds() * 1000}")
tmp_influence = -sum([
####################
# TODO: potential bottle neck, takes 17% execution time
# torch.sum(k * j).data.cpu().numpy()
####################
torch.sum(k * j).data for k, j in zip(grad_z_vec, s_test_vec)
]) / train_dataset_size
influences.append(tmp_influence)
display_progress("Calc. influence function: ", i, train_dataset_size)
harmful = np.argsort(influences)
helpful = harmful[::-1]
return influences, harmful.tolist(), helpful.tolist(), test_id_num
