In psmits/mathhammr: Tools for Dice Roll Simulations in Warhammer40k 8th

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

if (!require(devtools)) {
    install.packages('devtools')
}
devtools::install_github('psmits/mathhammr')

library(dplyr)
library(magrittr)
library(purrr)
library(tidyr)
library(ggplot2)
library(mathhammr)

# 5 man squad of space marines shot a 5 man squad of chaos space marines with bolters at > 12" away.
hits <- to_attack(n= 5, skill = 3)
print(hits)

wounds <- to_wound(n = hits, str = 4, tgh = 4)
print(wounds)

damage <- to_save(n = wounds, sv = 3, ap = 0)
print(damage)

Let's try that 1000 times.

hits_many <- replicate(1000, to_attack(n = 5, skill = 3))
wounds_many <- map_dbl(hits_many, ~ to_wound(n = .x, str = 4, tgh = 4))
damage_many <- map_dbl(wounds_many, ~ to_save(n = .x, sv = 3, ap = 0))

results <- tibble(hits = hits_many,
                  wounds = wounds_many,
                  damage = damage_many) # damage on a bolter
results %>%
  gather(key = 'key', value = 'value') %>%
  mutate(key = case_when(key == 'hits' ~ 'Successful hit rolls',
                         key == 'wounds' ~ 'Successful wound rolls',
                         key == 'damage' ~ 'Unsaved wound rolls')) %>%
  ggplot() +
  geom_bar(aes(x = value, fill = key)) +
  facet_wrap(key ~ .) +
  labs(x = 'Result', y = 'Count') +
  theme(legend.position = 'none') +
  NULL

How about something more complicated. 30 Shoota boyz at a Rhino. Remembering Dakka, Dakka, Dakka.

hits_boyz <- replicate(1000, to_attack(n = 2 * 30, skill = 5, explode = 6))
wounds_boyz <- map_dbl(hits_boyz, ~ to_wound(n = .x, str = 4, tgh = 7))
damage_boyz <- map_dbl(wounds_boyz, ~ to_save(n = .x, sv = 3, ap = 0))

results <- tibble(hits = hits_boyz,
                  wounds = wounds_boyz,
                  damage = damage_boyz* 1) # damage on a bolter
results %>%
  gather(key = 'key', value = 'value') %>%
  mutate(key = case_when(key == 'hits' ~ 'Successful hit rolls',
                         key == 'wounds' ~ 'Successful wound rolls',
                         key == 'damage' ~ 'Unsaved wound rolls')) %>%
  ggplot() +
  geom_bar(aes(x = value, fill = key)) +
  geom_vline(xintercept = 10, colour = 'black') +
  facet_wrap(key ~ .) +
  labs(x = 'Result', y = 'Count') +
  theme(legend.position = 'none') +
  NULL

# and percent of simulations where boyz kill the rhino?
kill_percent <- (sum(damage_boyz >= 10) / length(damage_boyz)) * 100
print(kill_percent)