任何人都可以向我解释MatLAB代码这一行中发生了什么 [英] Can anyone explain to me what is going on in this line of MatLAB code

问题描述

y = rand(20,3); 
aa= unidrnd(2,20,3) - 1;
val = ( aa & y<1.366e-04) | (~aa & y<8.298e-04);
aa(val) = ~aa(val);

我有这个代码. 谁能向我解释这里发生了什么.我试图逐步了解它(调试)，但是我不明白在第4行中使用反'〜'以及还将'val'用作索引的目的.

I have this code. Can any one explain to me what is happening here. I have tried to understand it step by step (debugging) but I cannot understand the purpose of using inverse '~' in line 4 and also using 'val' as indices.

推荐答案

y = rand(20,3); 

创建一个均匀分布的随机数矩阵，y.

Creates a matrix of uniformly distributed random numbers, y.

aa= unidrnd(2,20,3) - 1;

创建一个均匀分布的随机整数矩阵，该矩阵从1到2，然后减去1.因此，aa是0和1的矩阵.

Creates a matrix of uniformly distributed random integers, that goes from 1 to 2, and then subtract one. Thus, aa is a matrix of 0s and 1s.

val = ( aa & y<1.366e-04) | (~aa & y<8.298e-04);

此行检查aa为1AND y<1.366e-04或aa为0 AND y<8.298e-04的所有值.请注意，这几乎不会发生，因为y是从0到1的均匀分布的数字，因为它们很小.

This line checks all the values where aa is 1AND y<1.366e-04 OR aa is 0 AND y<8.298e-04. Note that this barely happens, being y uniformly distributed numbers from 0 to 1, being them this smalls is unlikely.

aa(val) = ~aa(val);

取所有以前计算过的情况，并使aa从0变为1，或者如果在该索引中发生，则从1变为0.

Take all those cases computed before, and make aa change from 0 to 1 or from 1 to 0 if it happened in that index.

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