R：稀疏矩阵乘法与data.table和quanteda包？ [英] R: sparse matrix multiplication with data.table and quanteda package?

问题描述

我试图创建一个矩阵雕刻与稀疏矩阵和包称为quanteda，利用data.table包，与此线程相关在这里。

I am trying to create a matrix mulptiplication with sparse matrix and with the package called quanteda, utilising data.table package, related to this thread here. So

require(quanteda) 

mytext <- c("Let the big dogs hunt", "No holds barred", "My child is an honor student")     
myMatrix <-dfm(mytext, ignoredFeatures = stopwords("english"), stem = TRUE) #a data.table
as.matrix(myMatrix) %*% transpose(as.matrix(myMatrix))

在这里用quanteda包和稀疏矩阵得到矩阵乘法？

how can you get the matrix multiplication working here with quanteda package and sparse matrices?

推荐答案

这很好：

mytext <- c("Let the big dogs hunt", 
            "No holds barred", 
            "My child is an honor student")     
myMatrix <- dfm(mytext)

myMatrix %*% t(myMatrix)
## 3 x 3 sparse Matrix of class "dgCMatrix"
##       text1 text2 text3
## text1     5     .     .
## text2     .     3     .
## text3     .     .     6

无需使用 as.matrix 。注意，它不再是一个dfmSparse对象，因为它不再是特征的文档矩阵。

No need to coerce to a dense matrix using as.matrix(). Note that it is no longer a "dfmSparse" object because it's no longer a matrix of documents by features.

这篇关于R：稀疏矩阵乘法与data.table和quanteda包？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！