Sentence Comparison

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Description

Computes cosine values between sentences and/or documents

Usage

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costring(x,y,tvectors=tvectors,breakdown=FALSE)

Arguments

x

a character vector

y

a character vector

tvectors

the semantic space in which the computation is to be done (a numeric matrix where every row is a word vector)

breakdown

if TRUE, the function breakdown is applied to the input

Details

In the traditional LSA approach, the vector D for a document (or a sentence) consisting of the words (t1, . , tn) is computed as

D = ∑\limits_{i=1}^n t_n

This function computes the cosine between two documents (or sentences) or the cosine between a single word and a document (or sentence).

The format of x (or y) can be of the kind x <- "word1 word2 word3" , but also of the kind x <- c("word1", "word2", "word3"). This allows for simple copy&paste-inserting of text, but also for using character vectors, e.g. the output of neighbors().

To import a document Document.txt to from a directory for comparisons, set your working directory to this directory using setwd(). Then use the following command lines:

fileName1 <- "Alice_in_Wonderland.txt"
x <- readChar(fileName1, file.info(fileName1)$size)

Value

A numeric giving the cosine between the input sentences/documents

Author(s)

Fritz Günther

References

Landauer, T.K., & Dumais, S.T. (1997). A solution to Plato's problem: The Latent Semantic Analysis theory of acquisition, induction and representation of knowledge. Psychological Review, 104, 211-240.

Dennis, S. (2007). How to use the LSA Web Site. In T. K. Landauer, D. S. McNamara, S. Dennis, & W. Kintsch (Eds.), Handbook of Latent Semantic Analysis (pp. 35-56). Mahwah, NJ: Erlbaum.

http://lsa.colorado.edu/

See Also

cosine, Cosine, multicos, multicostring

Examples

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data(wonderland)
costring("Alice was beginning to get very tired.",
      "A white rabbit with a clock ran close to her.",
      tvectors=wonderland)