我试图使这段代码运行得更快,但是我找不到其他可以加快速度的技巧。
我得到大约3微秒的运行时间,问题是我将此函数调用了数百万次,而该过程最终要花费很长时间。我在Java中具有相同的实现(仅具有基本的for循环),并且基本上,即使对于大型训练数据(这是针对ANN),计算也是即时的
有没有办法加快速度?
我正在Windows 10上运行Python 2.7,numba 0.43.1和numpy 1.16.3
x = True
expected = 0.5
eligibility = np.array([0.1,0.1,0.1])
positive_weight = np.array([0.2,0.2,0.2])
total_sq_grad_positive = np.array([0.1,0.1,0.1])
learning_rate = 1
@nb.njit(fastmath= True, cache = True)
def update_weight_from_post_post_jit(x, expected,eligibility,positive_weight,total_sq_grad_positive,learning_rate):
if x:
g = np.multiply(eligibility,(1-expected))
else:
g = np.negative(np.multiply(eligibility,expected))
gg = np.multiply(g,g)
total_sq_grad_positive = np.add(total_sq_grad_positive,gg)
#total_sq_grad_positive = np.where(divide_by_zero,total_sq_grad_positive, tsgp_temp)
temp = np.multiply(learning_rate, g)
temp2 = np.sqrt(total_sq_grad_positive)
#temp2 = np.where(temp2 == 0,1,temp2 )
temp2[temp2 == 0] = 1
temp = np.divide(temp,temp2)
positive_weight = np.add(positive_weight, temp)
return [positive_weight, total_sq_grad_positive]
答案 0 :(得分:1)
编辑:@ max9111似乎正确。不必要的临时数组是开销的来源。
对于函数的当前语义,似乎有两个无法避免的临时数组-返回值[positive_weight, total_sq_grad_positive]
。但是,令我惊讶的是,您可能打算使用此功能来更新这两个输入数组。如果是这样,通过就地进行所有操作,我们将获得最大的加速。像这样:
import numba as nb
import numpy as np
x = True
expected = 0.5
eligibility = np.array([0.1,0.1,0.1])
positive_weight = np.array([0.2,0.2,0.2])
total_sq_grad_positive = np.array([0.1,0.1,0.1])
learning_rate = 1
@nb.njit(fastmath= True, cache = True)
def update_weight_from_post_post_jit(x, expected,eligibility,positive_weight,total_sq_grad_positive,learning_rate):
for i in range(eligibility.shape[0]):
if x:
g = eligibility[i] * (1-expected)
else:
g = -(eligibility[i] * expected)
gg = g * g
total_sq_grad_positive[i] = total_sq_grad_positive[i] + gg
temp = learning_rate * g
temp2 = np.sqrt(total_sq_grad_positive[i])
if temp2 == 0: temp2 = 1
temp = temp / temp2
positive_weight[i] = positive_weight[i] + temp
@nb.jit
def test(n, *args):
for i in range(n): update_weight_from_post_post_jit(*args)
如果您不希望更新输入数组,则可以使用
positive_weight = positive_weight.copy()
total_sq_grad_positive = total_sq_grad_positive.copy()
并按照原始代码返回它们。这并没有那么快,但是仍然更快。
我不确定是否可以将其优化为“瞬时”。我对Java能够做到这一点感到有些惊讶,因为这对我来说似乎是一个相当复杂的功能,并且需要耗时的操作,例如 sqrt
。
但是,您是否在调用此函数的函数上使用了nb.jit
?像这样:
@nb.jit
def test(n):
for i in range(n): update_weight_from_post_post_jit(x, expected,eligibility,positive_weight,total_sq_grad_positive,learning_rate)
在我的计算机上,这将运行时间缩短了一半,这是有道理的,因为Python函数调用的开销非常大。