Matlab的bsxfun()代码 [英] Matlab's bsxfun() code

问题描述

这是做什么的?

u = [5 6];
s = [1 1];
data1    =[randn(10,1) -1*ones(10,1)];
data2    =[randn(10,1) ones(10,1)];
data     = [data1; data2];
deviance = bsxfun(@minus,data,u);  
deviance = bsxfun(@rdivide,deviance,s); 
deviance = deviance .^ 2; 
deviance = bsxfun(@plus,deviance,2*log(abs(s)));
[dummy,mini] = min(deviance,[],2);

在没有bsxfun的情况下是否有等效的方法?

Is there an equivalent way of doing this without bsxfun?

推荐答案

函数 BSXFUN 将通过复制两个输入参数的尺寸，使其大小相互匹配，来执行请求的按元素操作(函数句柄参数).在这种情况下，您可以通过复制变量u和s自己使用函数 REPMAT 进行设置与data相同的大小.然后，您可以使用标准的逐元素算术运算符:

The function BSXFUN will perform the requested element-wise operation (function handle argument) by replicating dimensions of the two input arguments so that they match each other in size. You can avoid the use of BSXFUN in this case by replicating the variables u and s yourself using the function REPMAT to make them each the same size as data. Then you can use the standard element-wise arithmetic operators:

u = repmat(u,size(data,1),1);  %# Replicate u so it becomes a 20-by-2 array
s = repmat(s,size(data,1),1);  %# Replicate s so it becomes a 20-by-2 array
deviance = ((data-u)./s).^2 + 2.*log(abs(s));  %# Shortened to one line

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