def trainTasks(train_file, tasks, fold_num, output_folder=None, param_file="params.xml"):
"""
Given a training instance file and a list of tasks, adapt the training
vectors to fit the tasks and build an SVM model for each of them.
"""
global classifier
if not output_folder:
output_folder = "models"
output_folder = os.path.join(output_folder, "fold-{0:02d}".format(fold_num + 1))
if not os.path.exists(output_folder):
os.makedirs(output_folder)
parameters = readParams(param_file)
assert len(parameters) == len(
tasks
), "The parameters file contains parameters for {0} tasks, whereas there are {1}.".format(
len(parameters), len(tasks)
)
model_files = []
labels, instances = read_problem(train_file)
for i, task in enumerate(tasks):
print "---training task {0:03d}/{1:03d}".format(i + 1, len(tasks))
new_labels = [int(task[label]) for label in labels]
params = parameters[i]
paramstring = ""
for param, value in params.items():
paramstring += " {0} {1}".format(param, value)
if classifier == "libsvm" and "-b" not in params.keys():
paramstring += " -b 1"
paramstring += " -q"
model_file = os.path.join(output_folder, os.path.basename(train_file) + ".task{0:03d}.model".format(i + 1))
model = train(new_labels, instances, paramstring)
save_model(model_file, model)
model_files.append(model_file)
return model_files
def getPredictions(test_file, tasks, model_files, fold_num, debug=False):
"""
Returns probability values of the +1 class per task as well as task
accuracies (classification accuracies per task).
Requires a test instance file, a list of tasks, and corresponding model
files. Transform the vectors to fit the tasks and classifies them against
the matching SVM model.
"""
assert len(tasks) == len(model_files), "Not as many model files as tasks"
labels, instances = read_problem(test_file)
models = []
print "---Loading models..."
for model_file in model_files:
models.append(load_model(model_file))
task_accuracies = [0.0 for _ in range(len(tasks))]
print "---Classifying instances..."
predictions = []
if debug:
debug_files = [
open(os.path.basename(test_file) + ".fold{0:02d}.task{1:03d}.test".format(fold_num + 1, i + 1), "w")
for i in range(len(tasks))
]
for label, instance in zip(labels, instances):
instance_predictions = []
for i, (model, task) in enumerate(zip(models, tasks)):
new_label = int(task[label])
if debug:
o_instance = [":".join([str(idx), str(val)]) for idx, val in sorted(instance.items())]
debug_files[i].write("{0} {1}\n".format(new_label, " ".join(o_instance)))
global classifier
if classifier == "liblinear":
pred_labels, ACC, pred_values, label_order = predict([new_label], [instance], model)
assert len(pred_values[0]) == 1
pred_value = pred_values[0][0]
# If the label order is reversed, reverse the sign of the distance value.
if label_order == [-1, 1]:
pred_value = -pred_value
# Normalize the value if it's not a probability value.
pred_value = normalizePrediction(pred_value)
elif classifier == "libsvm":
pred_labels, (ACC, MSC, SCC), pred_values = predict([new_label], [instance], model, options="-b 1")
label_order = model.get_labels()
pred_value = pred_values[0][label_order.index(1)]
# Add the value to the instance predictions.
instance_predictions.append(pred_value)
# Add one if the prediction was accurate
if new_label == pred_labels[0]:
task_accuracies[i] += 1
predictions.append(instance_predictions)
if debug:
for debug_file in debug_files:
debug_file.close()
print "---Done."
task_accuracies = [score / len(instances) for score in task_accuracies]
return predictions, task_accuracies
