高斯求积

import paddle

nodes = paddle.to_tensor([-0.7745966692, 0.0, 0.7745966692], dtype="float32")
weights = paddle.to_tensor([0.5555555556, 0.8888888889, 0.5555555556], dtype="float32")

a = paddle.to_tensor(0.0, dtype="float32")
b = paddle.to_tensor(3.1415926536, dtype="float32")
x = 0.5 * (b - a) * nodes + 0.5 * (a + b)
y = paddle.sin(x)
result = 0.5 * (b - a) * paddle.sum(weights * y)