calcPerClusterMappingMetric fails with singleton query_cluster_labels

[amcdavid]

library(symphony)
# For the sake of an easy to get a `query` object
rmarkdown::render('vignettes/quickstart_tutorial.Rmd')
labels = sample(1:5, size = nrow(query$meta_data), replace = TRUE)
calcPerClusterMappingMetric(reference, query, query_cluster_labels = labels)

Calculating mapping confidence for 5 query clusters
query_cluster distance_score
1 5 12.908458
2 3 2.888485
3 2 3.209513
4 1 36.630791
5 4 7.808481

calcPerClusterMappingMetric works with typical data.

labels_singleton = labels
labels_singleton[1] = 6
calcPerClusterMappingMetric(reference, query, query_cluster_labels = labels_singleton)

Calculating mapping confidence for 6 query clusters
Error in base::rowMeans(x, na.rm = na.rm, dims = dims, ...) :
'x' must be an array of at least two dimensions

The PCA matrix is subset with an arbitrary index, and if the index has length one, R "helpfully" coerces it to a vector. Issue arises regardless of the value of u.

symphony/R/confidenceScores.R

Line 83 in d9d50dc

cluster_Zq_pca = query$Zq_pca[, cluster_idx]