# coding: utf-8
import sys
sys.path.append('..')  # 부모 디렉터리의 파일을 가져올 수 있도록 설정
import numpy as np
from common.optimizer import SGD
from dataset import spiral
import matplotlib.pyplot as plt
from ch01.two_layer_net import TwoLayerNet


# 하이퍼파라미터 설정
max_epoch = 300
batch_size = 30
hidden_size = 10
learning_rate = 1.0

# 데이터 읽기, 모델과 옵티마이저 생성
x, t = spiral.load_data()
model = TwoLayerNet(input_size=2, hidden_size=hidden_size, output_size=3)
optimizer = SGD(lr=learning_rate)

# 학습에 사용하는 변수
data_size = len(x)
max_iters = data_size // batch_size
total_loss = 0
loss_count = 0
loss_list = []

for epoch in range(max_epoch):
    # 데이터 뒤섞기
    idx = np.random.permutation(data_size)
    x = x[idx]
    t = t[idx]

    for iters in range(max_iters):
        batch_x = x[iters*batch_size:(iters+1)*batch_size]
        batch_t = t[iters*batch_size:(iters+1)*batch_size]

        # 기울기를 구해 매개변수 갱신
        loss = model.forward(batch_x, batch_t)
        model.backward()
        optimizer.update(model.params, model.grads)

        total_loss += loss
        loss_count += 1

        # 정기적으로 학습 경과 출력
        if (iters+1) % 10 == 0:
            avg_loss = total_loss / loss_count
            print('| 에폭 %d |  반복 %d / %d | 손실 %.2f'
                  % (epoch + 1, iters + 1, max_iters, avg_loss))
            loss_list.append(avg_loss)
            total_loss, loss_count = 0, 0


# 학습 결과 플롯
plt.plot(np.arange(len(loss_list)), loss_list, label='train')
plt.xlabel('반복 (x10)')
plt.ylabel('손실')
plt.show()

# 경계 영역 플롯
h = 0.001
x_min, x_max = x[:, 0].min() - .1, x[:, 0].max() + .1
y_min, y_max = x[:, 1].min() - .1, x[:, 1].max() + .1
xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h))
X = np.c_[xx.ravel(), yy.ravel()]
score = model.predict(X)
predict_cls = np.argmax(score, axis=1)
Z = predict_cls.reshape(xx.shape)
plt.contourf(xx, yy, Z)
plt.axis('off')

# 데이터점 플롯 
x, t = spiral.load_data()
N = 100
CLS_NUM = 3
markers = ['o', 'x', '^']
for i in range(CLS_NUM):
    plt.scatter(x[i*N:(i+1)*N, 0], x[i*N:(i+1)*N, 1], s=40, marker=markers[i])
plt.show()
