# Random MIC Values/Disk Zones/SIR Generation

These functions can be used for generating random MIC values and disk
diffusion diameters, for AMR data analysis practice. By providing a
microorganism and antimicrobial drug, the generated results will reflect
reality as much as possible.

## Usage

``` r
random_mic(size = NULL, mo = NULL, ab = NULL, skew = "right",
  severity = 1, ...)

random_disk(size = NULL, mo = NULL, ab = NULL, skew = "left",
  severity = 1, ...)

random_sir(size = NULL, prob_SIR = c(0.33, 0.33, 0.33), ...)
```

## Arguments

- size:

  Desired size of the returned vector. If used in a
  [data.frame](https://rdrr.io/r/base/data.frame.html) call or `dplyr`
  verb, will get the current (group) size if left blank.

- mo:

  Any [character](https://rdrr.io/r/base/character.html) that can be
  coerced to a valid microorganism code with
  [`as.mo()`](https://amr-for-r.org/reference/as.mo.md). Can be the same
  length as `size`.

- ab:

  Any [character](https://rdrr.io/r/base/character.html) that can be
  coerced to a valid antimicrobial drug code with
  [`as.ab()`](https://amr-for-r.org/reference/as.ab.md).

- skew:

  Direction of skew for MIC or disk values, either `"right"` or
  `"left"`. A left-skewed distribution has the majority of the data on
  the right.

- severity:

  Skew severity; higher values will increase the skewedness. Default is
  `2`; use `0` to prevent skewedness.

- ...:

  Ignored, only in place to allow future extensions.

- prob_SIR:

  A vector of length 3: the probabilities for "S" (1st value), "I" (2nd
  value) and "R" (3rd value).

## Value

class `mic` for `random_mic()` (see
[`as.mic()`](https://amr-for-r.org/reference/as.mic.md)) and class
`disk` for `random_disk()` (see
[`as.disk()`](https://amr-for-r.org/reference/as.disk.md))

## Details

Internally, MIC and disk zone values are sampled based on clinical
breakpoints defined in the
[clinical_breakpoints](https://amr-for-r.org/reference/clinical_breakpoints.md)
data set. To create specific generated values per bug or drug, set the
`mo` and/or `ab` argument. The MICs are sampled on a log2 scale and
disks linearly, using weighted probabilities. The weights are based on
the `skew` and `severity` arguments:

- `skew = "right"` places more emphasis on lower MIC or higher disk
  values.

- `skew = "left"` places more emphasis on higher MIC or lower disk
  values.

- `severity` controls the exponential bias applied.

## Examples

``` r
random_mic(25)
#> Class 'mic'
#>  [1] 0.008    0.125    4        32       1        0.004    0.008    0.0002  
#>  [9] 0.125    2        0.008    0.008    0.016    0.125    0.064    <=0.0001
#> [17] 0.0005   0.0002   0.5      0.002    0.002    0.25     16       <=0.0001
#> [25] 0.002   
random_disk(25)
#> Class 'disk'
#>  [1] 25 47 24 47 38 28 36 33 31 50 41 29 40 31 44 45 37 40 44 49  9 48 20 37 47
random_sir(25)
#> Class 'sir'
#>  [1] S S R R S S I S I S S I S R I I I I S I R I I I I

# add more skewedness, make more realistic by setting a bug and/or drug:
disks <- random_disk(100, severity = 2, mo = "Escherichia coli", ab = "CIP")
plot(disks)

# `plot()` and `ggplot2::autoplot()` allow for coloured bars if `mo` and `ab` are set
plot(disks, mo = "Escherichia coli", ab = "CIP", guideline = "CLSI 2025")


# \donttest{
random_mic(25, "Klebsiella pneumoniae") # range 0.0625-64
#> Class 'mic'
#>  [1] 2      0.001  4      0.008  0.0005 0.0005 0.0005 0.0002 0.0002 >=64  
#> [11] 0.0002 1      0.5    0.002  0.5    0.002  0.001  0.032  0.008  0.004 
#> [21] 0.032  0.0002 0.0005 0.002  0.001 
random_mic(25, "Klebsiella pneumoniae", "meropenem") # range 0.0625-16
#> Class 'mic'
#>  [1] <=0.5 <=0.5 2     <=0.5 1     <=0.5 <=0.5 <=0.5 <=0.5 1     <=0.5 <=0.5
#> [13] <=0.5 1     <=0.5 1     <=0.5 <=0.5 <=0.5 <=0.5 <=0.5 <=0.5 2     1    
#> [25] 2    
random_mic(25, "Streptococcus pneumoniae", "meropenem") # range 0.0625-4
#> Class 'mic'
#>  [1] 0.125 0.125 1     0.25  0.5   0.125 0.125 0.125 0.125 0.125 0.125 0.125
#> [13] 1     0.125 0.5   1     0.125 0.25  0.5   0.25  0.5   0.5   0.5   0.125
#> [25] 0.25 

random_disk(25, "Klebsiella pneumoniae") # range 8-50
#> Class 'disk'
#>  [1] 32 21 23 21 14 22 25 29 29 28 34 34 34 33 13 28 33 34 32 25 18 26 13 21 33
random_disk(25, "Klebsiella pneumoniae", "ampicillin") # range 11-17
#> Class 'disk'
#>  [1] 20 21 15 22 16 22 16 14 21 17 15 19 20 17 18 21 16 20 11 22 19 18 19 11 21
random_disk(25, "Streptococcus pneumoniae", "ampicillin") # range 12-27
#> Class 'disk'
#>  [1] 29 25 31 17 29 21 31 34 33 31 29 30 23 20 33 20 34 32 35 26 26 26 34 30 33
# }
```