def outer_cross_validation(kernel_train, x_test, y_train, y_test, async_res, balanced=False): best_c, best_acc = select_best_c(async_res) y_hat = launch_svc(kernel_train, x_test, y_train, best_c, balanced) result = dict() result['best_c'] = best_c result['best_acc'] = best_acc result['evaluation'] = evaluate_prediction(y_test, y_hat) result['y_hat'] = y_hat return result
def inner_grid_search(shared_x, indices, train_index, inner_train_index, inner_test_index, y_train, y_test, alpha, positive=False): x_train = shared_x[indices[train_index[inner_train_index]], :] x_test = shared_x[indices[train_index[inner_test_index]], :] y_hat = launch_lasso(x_train, x_test, y_train, alpha, positive) res = evaluate_prediction(y_test, y_hat) return res['accuracy']
def outer_cross_validation(shared_x, indices, train_index, test_index, y_train, y_test, async_res, positive=False): best_alpha, best_acc = select_best_alpha(async_res) x_train = shared_x[indices[train_index], :] x_test = shared_x[indices[test_index], :] y_hat = launch_lasso(x_train, x_test, y_train, best_alpha, positive) result = dict() result['best_alpha'] = best_alpha result['best_acc'] = best_acc result['evaluation'] = evaluate_prediction(y_test, y_hat) result['y_hat'] = y_hat return result
def lasso_binary_classification(image_list, diagnosis_list, output_directory, existing_gram_matrix=None, mask_zeros=True, scale_data=False, positive=False, outer_folds=10, inner_folds=10, n_threads=10, alphas=np.arange(0.1, 1.1, 0.1), save_gram_matrix=False, save_subject_classification=False, save_weights=True, save_features_image=True): results = dict() dx_filter = np.unique(diagnosis_list) print 'Loading ' + str(len(image_list)) + ' subjects' x0, orig_shape, data_mask = load_data(image_list, mask=mask_zeros) print 'Subjects loaded' if scale_data: x_all = scale(x0) else: x_all = x0 # if existing_gram_matrix is not None: # gram_matrix = existing_gram_matrix # if (gram_matrix.shape[0] != gram_matrix.shape[1]) | (gram_matrix.shape[0] != len(image_list)): # raise ValueError('The existing Gram matrix must be a square matrix with number of rows and columns equal to the number of images.') # else: # print 'Calculating Gram matrix' # gram_matrix = gram_matrix_linear(x_all) # print 'Gram matrix calculated' # if save_gram_matrix: # np.savetxt(join(output_directory, 'gram_matrix.txt'), gram_matrix) # BaseManager.register('ndarray', type(x_all)) # manager = BaseManager() # manager.start() # shared_x = manager.ndarray(x_all.shape, buffer=x_all) shared_x = sharedmem.copy(x_all) x_all = None gc.collect() for i in range(len(dx_filter)): for j in range(i + 1, len(dx_filter)): dx1 = dx_filter[i] dx2 = dx_filter[j] ind1 = [] ind2 = [] for k in range(len(diagnosis_list)): if diagnosis_list[k] == dx1: ind1.append(k) if diagnosis_list[k] == dx2: ind2.append(k) indices = ind1 + ind2 indices = np.array(indices) current_subjects = [image_list[k] for k in indices] current_diagnosis = [diagnosis_list[k] for k in indices] # x = x_all[indices, :] y = np.array([0] * len(ind1) + [1] * len(ind2)) # gm = gram_matrix[indices, :][:, indices] classification_str = dx1 + '_vs_' + dx2 + ('_positive' if positive else '') print 'Running ' + dx1 + ' vs ' + dx2 + ' classification' y_hat, coefficients, intersect, alpha = nested_folds( shared_x, indices, y, alphas, positive=positive, outer_folds=outer_folds, inner_folds=inner_folds, n_threads=n_threads) evaluation = evaluate_prediction(y, y_hat) print '\nTrue positive %0.2f' % len(evaluation['predictions'][0]) print 'True negative %0.2f' % len(evaluation['predictions'][1]) print 'False positive %0.2f' % len(evaluation['predictions'][2]) print 'False negative %0.2f' % len(evaluation['predictions'][3]) print 'Accuracy %0.2f' % evaluation['accuracy'] print 'Balanced accuracy %0.2f' % evaluation['balanced_accuracy'] print 'Sensitivity %0.2f' % evaluation['sensitivity'] print 'Specificity %0.2f' % evaluation['specificity'] print 'Positive predictive value %0.2f' % evaluation['ppv'] print 'Negative predictive value %0.2f \n' % evaluation['npv'] if save_weights or save_features_image: weights_orig = revert_mask(coefficients, data_mask, orig_shape) if save_weights: np.save( join(output_directory, classification_str + '__intersect'), intersect) np.save( join(output_directory, classification_str + '__weights'), weights_orig) if save_features_image: weights_to_nifti( weights_orig, image_list[0], join(output_directory, classification_str + '__features_image.nii')) if save_subject_classification: save_subjects_prediction( current_subjects, current_diagnosis, y, y_hat, join(output_directory, classification_str + '__subjects.csv')) results[(dx1, dx2)] = evaluate_prediction(y, y_hat) results_to_csv( results, dx_filter, join(output_directory, 'resume' + ('_positive' if positive else '') + '.csv'))
def inner_grid_search(kernel_train, x_test, y_train, y_test, c, balanced=False): y_hat = launch_svc(kernel_train, x_test, y_train, c, balanced) res = evaluate_prediction(y_test, y_hat) return res['accuracy']
def linear_svm_binary_classification(image_list, diagnose_list, output_directory, mask_zeros=True, balanced=False, outer_folds=10, inner_folds=10, n_threads=10, c_range=np.logspace(-6, 2, 17), save_gram_matrix=False, save_subject_classification=False, save_original_weights=False, save_features_image=True): results = dict() dx_filter = np.unique(diagnose_list) print 'Loading ' + str(len(image_list)) + ' subjects' x0, orig_shape, data_mask = load_data(image_list, mask=mask_zeros) print 'Subjects loaded' print 'Calculating Gram matrix' x_all = scale(np.nan_to_num(x0)) gram_matrix = gram_matrix_linear(x_all) print 'Gram matrix calculated' if save_gram_matrix: np.savetxt(join(output_directory, 'gram_matrix.txt'), gram_matrix) # Allow loading precalculated gram_matrix? # gram_matrix = np.loadtxt(input_gram_matrix) for i in range(len(dx_filter)): for j in range(i + 1, len(dx_filter)): dx1 = dx_filter[i] dx2 = dx_filter[j] ind1 = [] ind2 = [] for k in range(len(diagnose_list)): if diagnose_list[k] == dx1: ind1.append(k) if diagnose_list[k] == dx2: ind2.append(k) indices = ind1 + ind2 current_subjects = [image_list[k] for k in indices] current_diagnosis = [diagnose_list[k] for k in indices] x = [x_all[k] for k in indices] y = np.array([0] * len(ind1) + [1] * len(ind2)) gm = gram_matrix[indices, :][:, indices] classification_str = dx1 + '_vs_' + dx2 + ('_balanced' if balanced else '_not_balanced') print 'Running ' + dx1 + ' vs ' + dx2 + ' classification' y_hat, w, c = nested_folds(gm, x, y, c_range, balanced=balanced, outer_folds=outer_folds, inner_folds=inner_folds, n_threads=n_threads) evaluation = evaluate_prediction(y, y_hat) print '\nTrue positive %0.2f' % len(evaluation['predictions'][0]) print 'True negative %0.2f' % len(evaluation['predictions'][1]) print 'False positive %0.2f' % len(evaluation['predictions'][2]) print 'False negative %0.2f' % len(evaluation['predictions'][3]) print 'Accuracy %0.2f' % evaluation['accuracy'] print 'Balanced accuracy %0.2f' % evaluation['balanced_accuracy'] print 'Sensitivity %0.2f' % evaluation['sensitivity'] print 'Specificity %0.2f' % evaluation['specificity'] print 'Positive predictive value %0.2f' % evaluation['ppv'] print 'Negative predictive value %0.2f \n' % evaluation['npv'] weights_orig = revert_mask(w, data_mask, orig_shape) if save_original_weights: np.save(join(output_directory, classification_str + '__weights'), weights_orig) if save_features_image: weights_to_nifti(weights_orig, image_list[0], join(output_directory, classification_str + '__features_image.nii')) if save_subject_classification: save_subjects_prediction(current_subjects, current_diagnosis, y, y_hat, join(output_directory, classification_str + '__subjects.csv')) results[(dx1, dx2)] = evaluate_prediction(y, y_hat) results_to_csv(results, dx_filter, join(output_directory, 'resume.csv'))