add drop = FALSE to matrices

[zkamvar]

I've also updated the data so that it will be safe from the R 4.0 change that will treat matrices as class "matrix", "array".

This will fix #18

  i <- incidence::incidence(as.Date('2020-01-23'))
si <- c(0.2, 0.5, 0.2, 0.1)
R0 <- 2

p <- projections::project(x = i,
  si = si,
  R = R0,
  n_sim = 1,  # doesn't work with 1 in project function
  R_fix_within = TRUE,
  n_days = 2, # doing 2 days as project function currently not working with one day - will only use first day though
  model = "poisson"
)
p
#> 
#> /// Incidence projections //
#> 
#>   // class: projections, matrix
#>   // 2 dates (rows); 1 simulations (columns)
#> 
#>  // first rows/columns:
#>            [,1]
#> 2020-01-24    2
#> 2020-01-25    6
#> 
#>  // dates:
#> [1] "2020-01-24" "2020-01-25"

^{Created on 2020-01-23 by the reprex package (v0.3.0)}

[codecov]

Codecov Report

Merging #19 into master will increase coverage by 2.17%.
The diff coverage is 87.5%.

@@            Coverage Diff             @@
##           master      #19      +/-   ##
==========================================
+ Coverage    92.6%   94.78%   +2.17%     
==========================================
  Files           9        9              
  Lines         230      230              
==========================================
+ Hits          213      218       +5     
+ Misses         17       12       -5

Impacted Files	Coverage Δ
R/conversion.R	100% <100%> (ø)	⬆️
R/build_projections.R	100% <100%> (ø)	⬆️
R/project.R	87.01% <86.36%> (+6.49%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7780512...23563be. Read the comment docs.