# Perplexity is too large

I am trying to run {Rtsne}. On pca dataset prepared by using dudi.pca from {ade4}.

For pca calculation I selected 40 components while specifying parameters for dudi.pca:

pca = dudi.pca(counts(sce_normalized), scannf=FALSE, nf=40)


{Rtsne} gives me an error: “perplexity is too large”, how could it be fixed?

The code I am trying to run is below:

name_of_file <- "dudi_pca.rds"
path_to_file <- paste0("/scratch/nv4e/scRNA-
seq/normalization/new_datasets/",
name_of_file, sep="")

• What are the dimensions of dudi_pca? – Devon Ryan Jan 21 '18 at 22:45
• The dimensions are 20 000 x 40 – Nikita Vlasenko Jan 22 '18 at 18:30
I was using dudi_pca incorrectly. The supplied parameter to as.matrix() should have been dudi_pca$li: rtsne_out <- Rtsne(as.matrix(dudi_pca$li), pca=FALSE)