改进距离计算 [英] Improving distance calculation

问题描述

我已经建立了自己的距离(我们称其为 d1 ).现在，我有了一个矩阵，需要为其计算距离.将 x 视为具有每个样本内容的矩阵，为获得距离矩阵而编写的代码如下:

I have build my own distance (let's call it d1). Now, I have a matrix for which I need to compute the distance. Considering x as the matrix with the content for each sample, the code written to get the distance matrix is the following:

# Build the matrix
  wDM <- matrix(0, nrow=nrow(x), ncol=nrow(x))

# Fill the matrix
  for (i in 1:(nrow(wDM)-1)){
    for (j in (i+1):nrow(wDM)){

    wDM[i,j] <- wDM[j,i] <- d1(x[i,], x[j,])

  }
}

我必须多次执行此过程.因此，我想知道是否有一种更快的方法来填充距离矩阵 wDM ，而不是使用两个for循环.

I have to implement this process several times. So, I was wondering if there is a faster way to fill the distance matrix wDM rather than using two for loops.

非常感谢您，

推荐答案

您可以使用 proxy包中的 dist().它允许您通过设置参数 method = #yourDistance 来指定用户定义的距离函数，默认值为 euclidean .在此处查看文档: https://cran.r-project.org/web/packages/proxy/proxy.pdf

You can use dist() from proxy package. It lets you specify user-defined distance function by setting the parameter method = #yourDistance default would be euclidean. Check the documentation here: https://cran.r-project.org/web/packages/proxy/proxy.pdf

这篇关于改进距离计算的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！