landscape_analysis.py 文件源码

def grid_search_gamma(rbf_svm, X, y):
    ## grid search - gamma only
    # use a full grid over all parameters
    param_grid = {'gamma': np.logspace(-15, 4, num = 5000, base = 2.0)}
    grid_search = GridSearchCV(rbf_svm, param_grid = param_grid, scoring = 'roc_auc',
                               cv = 10, pre_dispatch = '2*n_jobs', n_jobs = -1)
    # re-fit on the whole training data
    grid_search.fit(X, y)
    grid_search_scores = [score[1] for score in grid_search.grid_scores_]
    print('Best parameters : {}'.format(grid_search.best_params_))
    print('Best score : {}'.format(grid_search.best_score_))

    # set canvas
    fig, ax = plt.subplots(1, 1)
    # ax.scatter(X[:, 0], X[:, 1], c = y)
    ax.plot(param_grid['gamma'], grid_search_scores)
    ax.set_title('AUC = f(gamma, C = 1.0)', fontsize = 'large')
    ax.set_xlabel('gamma', fontsize = 'medium')
    ax.set_ylabel('AUC', fontsize = 'medium')

    return fig