R: Calculate the R-squared of a topic model.

CalcTopicModelR2 {textmineR} | R Documentation

## Calculate the R-squared of a topic model.

### Description

Function to calculate R-squared for a topic model. This uses a geometric interpretation of R-squared as the proportion of total distance each document is from the center of all the documents that is explained by the model.

### Usage

    CalcTopicModelR2(dtm, phi, theta, ...)

### Arguments

`dtm` | A documents by terms dimensional document term matrix of class `dgCMatrix` or of class `matrix`.
`phi` | A topics by terms dimensional matrix where each entry is p(term_i |topic_j)
`theta` | A documents by topics dimensional matrix where each entry is p(topic_j|document_d)
`...` | Other arguments to be passed to `TmParallelApply`. See note, below.

### Value

Returns an object of class `numeric` representing the proportion of variability in the data that is explained by the topic model.

### Note

This function performs parallel computation if `dtm` has more than 3,000 rows. The default is to use all available cores according to `detectCores`. However, this can be modified by passing the `cpus` argument when calling this function.

### Examples

    # Load a pre-formatted dtm and topic model
    data(nih_sample_dtm)
    data(nih_sample_topic_model)

    # Get the R-squared of the model
    r2 <- CalcTopicModelR2(dtm = nih_sample_dtm,
                         phi = nih_sample_topic_model$phi,
                         theta = nih_sample_topic_model$theta)

    r2

[Package textmineR version 3.0.5 Index]