inconsistent posterior data format

[Max Kuhn]

I think that there may be some matrix dimension dropping within the predict method. It usually gives a data frame back but drops to a numeric vector when a single data point is predicted:

library(sparsediscrim)

random <- t(matrix(rexp(20000, rate=.1), ncol=20))
colnames(random) <- paste0("x", 1:ncol(random))
response <- factor(rep(c('a','b'),10))

mod <- hdrda(random, response, gamma = 0, lambda = 0)

predict(mod, random[1:2,])$posterior
predict(mod, random[1,,drop = FALSE])$posterior

> sessionInfo()
R version 3.5.0 (2018-04-23)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS High Sierra 10.13.6

Matrix products: default
BLAS: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods  
[7] base     

other attached packages:
[1] sparsediscrim_0.2.4

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.18     rstudioapi_0.7   bindr_0.1.1     
 [4] magrittr_1.5     tidyselect_0.2.4 munsell_0.5.0   
 [7] colorspace_1.3-2 R6_2.2.2         rlang_0.2.1.9000
[10] plyr_1.8.4       dplyr_0.7.6      tools_3.5.0     
[13] grid_3.5.0       gtable_0.2.0     corpcor_1.6.9   
[16] yaml_2.2.0       lazyeval_0.2.1   assertthat_0.2.0
[19] tibble_1.4.2     crayon_1.3.4     bindrcpp_0.2.2  
[22] bdsmatrix_1.3-3  purrr_0.2.5      ggplot2_3.0.0   
[25] glue_1.3.0       compiler_3.5.0   pillar_1.3.0    
[28] scales_1.0.0     mvtnorm_1.0-7    pkgconfig_2.0.1 
``