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Author Topic: 阿姆达尔定律  (Read 219 times)
kingkin (OP)
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February 02, 2018, 01:04:25 AM
Merited by zhengbq (5)
 #1

其公式是这样的:
S=1/(1-a+a/n)
其中,a为并行计算部分所占比例,n为并行处理结点个数。这样,当1-a=0时,(即没有串行,只有并行)最大加速比s=n;当a=0时(即只有串行,没有并行),最小加速比s=1;当n→∞时,极限加速比s→ 1/(1-a),这也就是加速比的上限。例如,若串行代码占整个代码的25%,则并行处理的总体性能不可能超过4。这一公式已被学术界所接受,并被称做“阿姆达尔定律”,也称为“安达尔定理”(Amdahl law)。

那么这个公式有什么用呢?
1. 增加处理器数,将计算负载分布到更多处理器上,从而提高计算速度
2. 程序中可并行代码的比例决定你增加处理器(总核心数)的上限

所以以后,如果哪个币号称自己的速度多牛叉,请先看看他是怎么提升速度的,如果是增加处理器数,一般都是没问题的,从而避免被骗。

不免俗地求赞,谢谢。
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zhengbq
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February 02, 2018, 02:19:17 AM
 #2

其公式是这样的:
S=1/(1-a+a/n)
其中,a为并行计算部分所占比例,n为并行处理结点个数。这样,当1-a=0时,(即没有串行,只有并行)最大加速比s=n;当a=0时(即只有串行,没有并行),最小加速比s=1;当n→∞时,极限加速比s→ 1/(1-a),这也就是加速比的上限。例如,若串行代码占整个代码的25%,则并行处理的总体性能不可能超过4。这一公式已被学术界所接受,并被称做“阿姆达尔定律”,也称为“安达尔定理”(Amdahl law)。

那么这个公式有什么用呢?
1. 增加处理器数,将计算负载分布到更多处理器上,从而提高计算速度
2. 程序中可并行代码的比例决定你增加处理器(总核心数)的上限

所以以后,如果哪个币号称自己的速度多牛叉,请先看看他是怎么提升速度的,如果是增加处理器数,一般都是没问题的,从而避免被骗。

不免俗地求赞,谢谢。
估计很少人能懂,除非计算机专业的。
zerbzhang
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February 02, 2018, 02:25:16 AM
 #3

数理统计与数据分析
xiaomizhou2018
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February 02, 2018, 03:03:25 AM
 #4

发行币的人应该也知道吧…
ChapmanJane
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February 02, 2018, 10:32:12 AM
 #5

虽然我看不懂,但是感觉很厉害的样子……

qthml
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February 02, 2018, 10:51:20 AM
 #6

看不懂啊,蒙眼梭习惯了
bigcancer
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February 02, 2018, 11:33:31 AM
 #7

这就是理论上,实际上速度快慢是和交易量成正比的,大部分山寨币币比特币速度快就是因为交易量小,没可比性
cocoliuis999
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February 02, 2018, 11:44:55 AM
 #8

这个太高深了,我看这里百分之九十都看不懂。朋友你能举个简单的操作例子吗?弄点大家都能看懂的解释下,这样对需要的人很有必要。
wabesal
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February 02, 2018, 12:16:12 PM
 #9

趕快推一個
不然會被說看不懂裝懂
andizhang
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February 02, 2018, 01:12:22 PM
 #10

看都看不懂
bluelife
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February 02, 2018, 01:40:47 PM
 #11

还没有认真看过币的代码呢。估计看不懂啊
oxygen88
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February 02, 2018, 05:28:44 PM
 #12

太深奥了,完全没看懂 Cheesy
tcseek
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February 02, 2018, 05:31:45 PM
 #13

看不懂啊,山寨币就是拼运气。
sing1801
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February 02, 2018, 11:12:49 PM
 #14

我也看不懂 太復雜了

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yanzx
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February 03, 2018, 03:55:03 AM
 #15

理论和实际还是有差别的。不能全套公式。
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