Linear Classifier (선형분류)
SGDClassifier(alpha, average, class_weight, epsilon, eta0, fit_intercept, l1_ratio, learning_rate, loss, max_iter, n_iter, n_jobs, penalty, power_t, random_state, shuffle, tol, verbose, warm_start)
확률적 경사하강법(SGD, Stochastic Gradient Descent)을 이용하여 선형모델을 구현
붓꽃 데이터 셋에 선형분류 적용