y = 100 * (x1 - x0**2)**2 + (x0 - 1)**2
return y
logs = []
x0 = Variable(np.array(0.0))
x1 = Variable(np.array(2.0))
iters = 1000
lr = 0.001
for i in range(iters):
print(x0, x1)
y = rosenbrock(x0, x1)
x0.cleargrad()
x1.cleargrad()
y.backward()
logs.append([float(x0.data), float(x1.data), float(y.data)])
x0.data -= lr * x0.grad
x1.data -= lr * x1.grad
# 図を描画
import matplotlib.pyplot as plt
R = 0.01
x = np.arange(-2.0, 2.0, R)
y = np.arange(-1.0, 3.0, R)
X, Y = np.meshgrid(x, y)
import os, sys; sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
import numpy as np
# Import core_simple explicitly
from dezero.core_simple import Variable
from dezero.core_simple import setup_variable
setup_variable()
def f(x):
y = x ** 4 - 2 * x ** 2
return y
def gx2(x):
return 12 * x ** 2 - 4
logs = []
x = Variable(np.array(2.0))
iters = 200
for i in range(iters):
print(i, x)
y = f(x)
x.cleargrad()
y.backward()
x.data -= 0.01 * x.grad
