def test_trialwise_decoding():
# 5,6,7,10,13,14 are codes for executed and imagined hands/feet
subject_id = 1
event_codes = [5, 6, 9, 10, 13, 14]
# This will download the files if you don't have them yet,
# and then return the paths to the files.
physionet_paths = mne.datasets.eegbci.load_data(subject_id, event_codes)
# Load each of the files
parts = [
mne.io.read_raw_edf(path,
preload=True,
stim_channel='auto',
verbose='WARNING') for path in physionet_paths
]
# Concatenate them
raw = concatenate_raws(parts)
# Find the events in this dataset
events, _ = mne.events_from_annotations(raw)
# Use only EEG channels
eeg_channel_inds = mne.pick_types(raw.info,
meg=False,
eeg=True,
stim=False,
eog=False,
exclude='bads')
# Extract trials, only using EEG channels
epoched = mne.Epochs(raw,
events,
dict(hands=2, feet=3),
tmin=1,
tmax=4.1,
proj=False,
picks=eeg_channel_inds,
baseline=None,
preload=True)
# Convert data from volt to millivolt
# Pytorch expects float32 for input and int64 for labels.
X = (epoched.get_data() * 1e6).astype(np.float32)
y = (epoched.events[:, 2] - 2).astype(np.int64) # 2,3 -> 0,1
train_set = SignalAndTarget(X[:60], y=y[:60])
test_set = SignalAndTarget(X[60:], y=y[60:])
# Set if you want to use GPU
# You can also use torch.cuda.is_available() to determine if cuda is available on your machine.
cuda = False
set_random_seeds(seed=20170629, cuda=cuda)
n_classes = 2
in_chans = train_set.X.shape[1]
# final_conv_length = auto ensures we only get a single output in the time dimension
model = ShallowFBCSPNet(in_chans=in_chans,
n_classes=n_classes,
input_time_length=train_set.X.shape[2],
final_conv_length='auto').create_network()
if cuda:
model.cuda()
optimizer = optim.Adam(model.parameters())
rng = RandomState((2017, 6, 30))
losses = []
accuracies = []
for i_epoch in range(6):
i_trials_in_batch = get_balanced_batches(len(train_set.X),
rng,
shuffle=True,
batch_size=30)
# Set model to training mode
model.train()
for i_trials in i_trials_in_batch:
# Have to add empty fourth dimension to X
batch_X = train_set.X[i_trials][:, :, :, None]
batch_y = train_set.y[i_trials]
net_in = np_to_var(batch_X)
if cuda:
net_in = net_in.cuda()
net_target = np_to_var(batch_y)
if cuda:
net_target = net_target.cuda()
# Remove gradients of last backward pass from all parameters
optimizer.zero_grad()
# Compute outputs of the network
outputs = model(net_in)
# Compute the loss
loss = F.nll_loss(outputs, net_target)
# Do the backpropagation
loss.backward()
# Update parameters with the optimizer
optimizer.step()
# Print some statistics each epoch
model.eval()
print("Epoch {:d}".format(i_epoch))
for setname, dataset in (('Train', train_set), ('Test', test_set)):
# Here, we will use the entire dataset at once, which is still possible
# for such smaller datasets. Otherwise we would have to use batches.
net_in = np_to_var(dataset.X[:, :, :, None])
if cuda:
net_in = net_in.cuda()
net_target = np_to_var(dataset.y)
if cuda:
net_target = net_target.cuda()
outputs = model(net_in)
loss = F.nll_loss(outputs, net_target)
losses.append(float(var_to_np(loss)))
print("{:6s} Loss: {:.5f}".format(setname, float(var_to_np(loss))))
predicted_labels = np.argmax(var_to_np(outputs), axis=1)
accuracy = np.mean(dataset.y == predicted_labels)
accuracies.append(accuracy * 100)
print("{:6s} Accuracy: {:.1f}%".format(setname, accuracy * 100))
np.testing.assert_allclose(np.array(losses),
np.array([
0.91796708, 1.2714895, 0.4999536,
0.94365239, 0.39268905, 0.89928466,
0.37648854, 0.8940345, 0.35774994,
0.86749417, 0.35080773, 0.80767328
]),
rtol=1e-4,
atol=1e-5)
np.testing.assert_allclose(np.array(accuracies),
np.array([
55., 63.33333333, 71.66666667, 63.33333333,
81.66666667, 60., 78.33333333, 63.33333333,
83.33333333, 66.66666667, 80., 66.66666667
]),
rtol=1e-4,
atol=1e-5)
def test_cropped_decoding():
# 5,6,7,10,13,14 are codes for executed and imagined hands/feet
subject_id = 1
event_codes = [5, 6, 9, 10, 13, 14]
# This will download the files if you don't have them yet,
# and then return the paths to the files.
physionet_paths = mne.datasets.eegbci.load_data(subject_id,
event_codes,
update_path=False)
# Load each of the files
parts = [
mne.io.read_raw_edf(path,
preload=True,
stim_channel="auto",
verbose="WARNING") for path in physionet_paths
]
# Concatenate them
raw = concatenate_raws(parts)
# Find the events in this dataset
events, _ = mne.events_from_annotations(raw)
# Use only EEG channels
eeg_channel_inds = mne.pick_types(raw.info,
meg=False,
eeg=True,
stim=False,
eog=False,
exclude="bads")
# Extract trials, only using EEG channels
epoched = mne.Epochs(
raw,
events,
dict(hands=2, feet=3),
tmin=1,
tmax=4.1,
proj=False,
picks=eeg_channel_inds,
baseline=None,
preload=True,
)
# Convert data from volt to millivolt
# Pytorch expects float32 for input and int64 for labels.
X = (epoched.get_data() * 1e6).astype(np.float32)
y = (epoched.events[:, 2] - 2).astype(np.int64) # 2,3 -> 0,1
SignalAndTarget = namedtuple("SignalAndTarget", "X y")
train_set = SignalAndTarget(X[:60], y=y[:60])
test_set = SignalAndTarget(X[60:], y=y[60:])
# Set if you want to use GPU
# You can also use torch.cuda.is_available() to determine if cuda is available on your machine.
cuda = False
set_random_seeds(seed=20170629, cuda=cuda)
# This will determine how many crops are processed in parallel
input_time_length = 450
n_classes = 2
in_chans = train_set.X.shape[1]
# final_conv_length determines the size of the receptive field of the ConvNet
model = ShallowFBCSPNet(
in_chans=in_chans,
n_classes=n_classes,
input_time_length=input_time_length,
final_conv_length=12,
)
to_dense_prediction_model(model)
if cuda:
model.cuda()
optimizer = optim.Adam(model.parameters())
# determine output size
test_input = np_to_var(
np.ones((2, in_chans, input_time_length, 1), dtype=np.float32))
if cuda:
test_input = test_input.cuda()
out = model(test_input)
n_preds_per_input = out.cpu().data.numpy().shape[2]
print("{:d} predictions per input/trial".format(n_preds_per_input))
iterator = CropsFromTrialsIterator(
batch_size=32,
input_time_length=input_time_length,
n_preds_per_input=n_preds_per_input,
)
losses = []
accuracies = []
for i_epoch in range(4):
# Set model to training mode
model.train()
for batch_X, batch_y in iterator.get_batches(train_set, shuffle=False):
net_in = np_to_var(batch_X)
if cuda:
net_in = net_in.cuda()
net_target = np_to_var(batch_y)
if cuda:
net_target = net_target.cuda()
# Remove gradients of last backward pass from all parameters
optimizer.zero_grad()
outputs = model(net_in)
# Mean predictions across trial
# Note that this will give identical gradients to computing
# a per-prediction loss (at least for the combination of log softmax activation
# and negative log likelihood loss which we are using here)
outputs = th.mean(outputs, dim=2, keepdim=False)
loss = F.nll_loss(outputs, net_target)
loss.backward()
optimizer.step()
# Print some statistics each epoch
model.eval()
print("Epoch {:d}".format(i_epoch))
for setname, dataset in (("Train", train_set), ("Test", test_set)):
# Collect all predictions and losses
all_preds = []
all_losses = []
batch_sizes = []
for batch_X, batch_y in iterator.get_batches(dataset,
shuffle=False):
net_in = np_to_var(batch_X)
if cuda:
net_in = net_in.cuda()
net_target = np_to_var(batch_y)
if cuda:
net_target = net_target.cuda()
outputs = model(net_in)
all_preds.append(var_to_np(outputs))
outputs = th.mean(outputs, dim=2, keepdim=False)
loss = F.nll_loss(outputs, net_target)
loss = float(var_to_np(loss))
all_losses.append(loss)
batch_sizes.append(len(batch_X))
# Compute mean per-input loss
loss = np.mean(
np.array(all_losses) * np.array(batch_sizes) /
np.mean(batch_sizes))
print("{:6s} Loss: {:.5f}".format(setname, loss))
losses.append(loss)
# Assign the predictions to the trials
preds_per_trial = compute_preds_per_trial_from_crops(
all_preds, input_time_length, dataset.X)
# preds per trial are now trials x classes x timesteps/predictions
# Now mean across timesteps for each trial to get per-trial predictions
meaned_preds_per_trial = np.array(
[np.mean(p, axis=1) for p in preds_per_trial])
predicted_labels = np.argmax(meaned_preds_per_trial, axis=1)
accuracy = np.mean(predicted_labels == dataset.y)
accuracies.append(accuracy * 100)
print("{:6s} Accuracy: {:.1f}%".format(setname, accuracy * 100))
np.testing.assert_allclose(
np.array(losses),
np.array([
1.31657708,
1.73548156,
1.02950428,
1.43932164,
0.78677772,
1.12382019,
0.55920881,
0.87277424,
]),
rtol=1e-4,
atol=1e-5,
)
np.testing.assert_allclose(
np.array(accuracies),
np.array([
50.0,
46.66666667,
50.0,
46.66666667,
50.0,
46.66666667,
66.66666667,
50.0,
]),
rtol=1e-4,
atol=1e-5,
)