textmodel_ca implements correspondence analysis scaling on a dfm. The method is a fast/sparse version of function ca, and returns a special class of ca object.

textmodel_ca(x, smooth = 0, nd = NA, sparse = FALSE,
  residual_floor = 0.1)

Arguments

x

the dfm on which the model will be fit

smooth

a smoothing parameter for word counts; defaults to zero.

nd

Number of dimensions to be included in output; if NA (the default) then the maximum possible dimensions are included.

sparse

retains the sparsity if set to TRUE; set it to TRUE if x (the dfm) is too big to be allocated after converting to dense

residual_floor

specifies the threshold for the residual matrix for calculating the truncated svd.Larger value will reduce memory and time cost but might reduce accuracy; only applicable when sparse = TRUE

Details

svds in the RSpectra package is applied to enable the fast computation of the SVD.

Note

You may need to set sparse = TRUE) and increase the value of residual_floor to ignore less important information and hence to reduce the memory cost when you have a very big dfm. If your attempt to fit the model fails due to the matrix being too large, this is probably because of the memory demands of computing the \(V \times V\) residual matrix. To avoid this, consider increasing the value of residual_floor by 0.1, until the model can be fit.

References

Nenadic, O. and Greenacre, M. (2007). Correspondence analysis in R, with two- and three-dimensional graphics: The ca package. Journal of Statistical Software, 20 (3), http://www.jstatsoft.org/v20/i03/.

Examples

ieDfm <- dfm(data_corpus_irishbudget2010) wca <- textmodel_ca(ieDfm) summary(wca)
#> Length Class Mode #> sv 7 -none- numeric #> nd 1 -none- numeric #> rownames 14 -none- character #> rowmass 14 -none- numeric #> rowdist 14 -none- numeric #> rowinertia 14 -none- numeric #> rowcoord 98 -none- numeric #> rowsup 0 -none- logical #> colnames 5140 -none- character #> colmass 5140 -none- numeric #> coldist 5140 -none- numeric #> colinertia 5140 -none- numeric #> colcoord 35980 -none- numeric #> colsup 0 -none- logical #> call 2 -none- call