dice-calc 0.2.0

Advanced Calculator for Dice

PythonDice

This is a python package that includes a simple to use and powerful dice probability engine.

This package offers features and capabilities to calculate probabilities of arbitrary dice scripts including full capabilities of anydice.com.

Additionaly, separate to the engine, this package includes an easy-to-use custom built compiler that translates any valid anydice.com code into runnable python code.

This project is still in very early development but everything mentioned above should be complete. (project started October 2024)

Installation

pip install dice-calc

This package has no dependencies.

Basic Usage

Example #1:

Let's roll a single d20 dice (a d20 is a regular twenty sided-die)

from dice_calc.randvar import roll
X = roll(20)
print(X)

10.5 ± 5.77
 1:  5.00  ████
 2:  5.00  ████
 3:  5.00  ████
 4:  5.00  ████
 5:  5.00  ████
 6:  5.00  ████
 7:  5.00  ████
 8:  5.00  ████
 9:  5.00  ████
10:  5.00  ████
11:  5.00  ████
12:  5.00  ████
13:  5.00  ████
14:  5.00  ████
15:  5.00  ████
16:  5.00  ████
17:  5.00  ████
18:  5.00  ████
19:  5.00  ████
20:  5.00  ████
----------------------------------------------------------------------------------------

The numbers on the first line are the mean and std.

Example #2

Let's roll two d6 dice (a d6 is a regular six sided-die)

from dice_calc.randvar import roll
X = roll(2, 6)  # or roll(6) + roll(6)
print(X)

7.0 ± 2.42
 2:  2.78  ██
 3:  5.56  ████
 4:  8.33  ██████
 5: 11.11  █████████
 6: 13.89  ███████████
 7: 16.67  █████████████
 8: 13.89  ███████████
 9: 11.11  █████████
10:  8.33  ██████
11:  5.56  ████
12:  2.78  ██
----------------------------------------------------------------------------------------

Example #3

What about rolling a D20 plus a D6?

from dice_calc.randvar import roll
X = roll(20) + roll(6)
print(X)

14.0 ± 6.01
 2:  0.83  █
 3:  1.67  █
 4:  2.50  ██
 5:  3.33  ███
 6:  4.17  ███
 7:  5.00  ████
 8:  5.00  ████
 9:  5.00  ████
10:  5.00  ████
11:  5.00  ████
12:  5.00  ████
13:  5.00  ████
14:  5.00  ████
15:  5.00  ████
16:  5.00  ████
17:  5.00  ████
18:  5.00  ████
19:  5.00  ████
20:  5.00  ████
21:  5.00  ████
22:  4.17  ███
23:  3.33  ███
24:  2.50  ██
25:  1.67  █
26:  0.83  █
----------------------------------------------------------------------------------------

Example #4

What about the probability distribution of rolling two D20's with advantage (i.e. rolling two D20's and taking the highest number)

from dice_calc.randvar import roll
X = 1 @ roll(2, 20)
print(X)

13.82 ± 4.71
 1:  0.25  
 2:  0.75  █
 3:  1.25  █
 4:  1.75  █
 5:  2.25  ██
 6:  2.75  ██
 7:  3.25  ███
 8:  3.75  ███
 9:  4.25  ███
10:  4.75  ████
11:  5.25  ████
12:  5.75  ████
13:  6.25  █████
14:  6.75  █████
15:  7.25  ██████
16:  7.75  ██████
17:  8.25  ██████
18:  8.75  ███████
19:  9.25  ███████
20:  9.75  ████████
----------------------------------------------------------------------------------------

Example #5

Let's try a slightly more complex example.

Rolling a D20 with advantage + two D6's + 5

from dice_calc.randvar import roll
D20_adv = 1 @ roll(2, 20)
two_D6 = roll(2, 6)
result = D20_adv + two_D6 + 5
print(result)

25.82 ± 5.29
 8:  0.01  
 9:  0.03  
10:  0.10  
11:  0.21  
12:  0.38  
13:  0.63  
14:  0.96  █
15:  1.35  █
16:  1.78  █
17:  2.26  ██
18:  2.75  ██
19:  3.25  ███
20:  3.75  ███
21:  4.25  ███
22:  4.75  ████
23:  5.25  ████
24:  5.75  ████
25:  6.25  █████
26:  6.75  █████
27:  7.25  ██████
28:  7.47  ██████
29:  7.38  ██████
30:  6.99  █████
31:  6.26  █████
32:  5.20  ████
33:  3.78  ███
34:  2.57  ██
35:  1.57  █
36:  0.80  █
37:  0.27  
----------------------------------------------------------------------------------------

Complex Example:

Let's try calculating the total damage of the following attack on a boss in an RPG:

• TO HIT: 1d20 + 7 against 22 AC (less than 22 is a miss. rolling a 20 is a CRITICAL so double the damage die)
• DAMAGE: 2d8 + 4 blunt damange
• + 1d4 thunder damage
• + 1d10 + 3 radiant damange (half damage if the target succeeds a 16 DC wisdom saving throw, boss has +5 wis saving throw)

from dice_calc.randvar import roll, anydice_casting

@anydice_casting()
def calculate(to_hit_roll: int, save_roll: int):  # type hinting as int REQUIRED!!!
    if to_hit_roll + 7 < 22:  # miss
        return 0
    is_crit = (to_hit_roll == 20)
    dmg_die_mult = 2 if is_crit else 1
    blung_dmg = roll(2 * dmg_die_mult, 8) + 4
    thund_dmg = roll(1 * dmg_die_mult, 4)
    radiant_dmg = roll(1 * dmg_die_mult, 10) + 3
    if save_roll + 5 >= 16:  # save success
        radiant_dmg = radiant_dmg // 2
    return blung_dmg + thund_dmg + radiant_dmg


X = calculate(roll(20), roll(20))

# plotting code
from matplotlib import pyplot as plt
vals, probs = zip(*X.get_vals_probs())
plt.bar(vals, probs); plt.xlabel('Damage'); plt.ylabel('Probability');

Notice how we used the decorator @anydice_casting to use if conditions on dice inside of a custom function. Typehinting the input to int is required, the engine knows that you want to calculate the function many times based on all possible combinations of the input random variable.

Getting probabilities as dict

from dice_calc.randvar import roll
X = 1 @ roll(2, 20)  # D20 with advantage
pdf = dict(X.get_vals_probs())
print(pdf)

{1: 0.0025, 2: 0.0075, 3: 0.0125, 4: 0.0175, 5: 0.0225, 6: 0.0275, 7: 0.0325, 8: 0.0375, 9: 0.0425, 10: 0.0475, 11: 0.0525, 12: 0.0575, 13: 0.0625, 14: 0.0675, 15: 0.0725, 16: 0.0775, 17: 0.0825, 18: 0.0875, 19: 0.0925, 20: 0.0975}

plotting using matploblib

from dice_calc.randvar import roll
X = 1 @ roll(2, 20) + 8  # D20 with advantage + 8

# plotting code
from matplotlib import pyplot as plt
vals, probs = zip(*X.get_vals_probs())
percent = [p * 100 for p in probs]
plt.bar(vals, percent); plt.xlabel('Roll'); plt.ylabel('Probability %');

compiling anydice.com code

anydice is a powerful and popular online dice calculater which inspired the creation of this package. Any* valid code from anydice can be converted to valid python code using this package in a single function call.

Below we take an example piece of code from the anydice articles legend of the five rings.

We convert it using the function compile_anydice and then execute it using our package (p.s. don't forget to import all the library functions as we do below).

from dice_calc.parser.parse_and_exec import compile_anydice

EXAMPLE_CODE = """
function: convert SUM:n {
 if SUM >= 1000 {
  TENSROLLED: SUM / 1000
  result: SUM - TENSROLLED * 990 + TENSROLLED d [explode d10]
 }
 result: SUM
}

output [convert [highest 3 of 6d{1..9, 1000}]] named "6k3 exploded after keeping"
"""

print(compile_anydice(EXAMPLE_CODE))

@anydice_casting()
def convert_X(SUM: int):
  if SUM >= 1000:
    TENSROLLED = SUM // 1000
    return SUM - TENSROLLED * 990 + roll(TENSROLLED, explode_X(roll(10)))
  
  return SUM

output(convert_X(highest_X_of_X(3, roll(6, Seq([myrange(1, 9), 1000])))), named=f"6k3 exploded after keeping")

# IMPORT EVERYTHING
from dice_calc.randvar import RV, Seq, anydice_casting, output, roll, settings_set
from dice_calc.utils import myrange
from dice_calc.funclib import absolute as absolute_X, contains as X_contains_X, count_in as count_X_in_X, explode as explode_X, highest_N_of_D as highest_X_of_X, lowest_N_of_D as lowest_X_of_X, middle_N_of_D as middle_X_of_X, highest_of_N_and_N as highest_of_X_and_X, lowest_of_N_and_N as lowest_of_X_and_X, maximum_of as maximum_of_X, reverse as reverse_X, sort as sort_X

# EXECUTE CODE FROM COMPILE_ANYDICE
@anydice_casting()
def convert_X(SUM: int):
  if SUM >= 1000:
    TENSROLLED = SUM // 1000
    return SUM - TENSROLLED * 990 + roll(TENSROLLED, explode_X(roll(10)))
  
  return SUM

output(convert_X(highest_X_of_X(3, roll(6, Seq([myrange(1, 9), 1000])))), named=f"6k3 exploded after keeping")

6k3 exploded after keeping 26.53 ± 8.32
  3:  0.00  
  4:  0.00  
  5:  0.00  
  6:  0.01  
  7:  0.02  
  8:  0.04  
  9:  0.09  
 10:  0.17  
 11:  0.29  █
 12:  0.48  █
 13:  0.76  █
 14:  1.12  ██
 15:  1.62  ███
 16:  2.22  ████
 17:  2.92  █████
 18:  3.71  ███████
 19:  4.55  ████████
 20:  5.31  █████████
 21:  6.00  ███████████
 22:  6.40  ███████████
 23:  6.51  ████████████
 24:  6.20  ███████████
 25:  5.61  ██████████
 26:  4.65  ████████
 27:  3.78  ███████
 28:  3.14  ██████
 29:  3.45  ██████
 30:  3.40  ██████
 31:  3.32  ██████
 32:  3.16  ██████
 33:  2.93  █████
 34:  2.60  █████
 35:  2.21  ████
 36:  1.78  ███
 37:  1.39  ██
 38:  1.13  ██
 39:  1.15  ██

 ... output cropped ...
-------------------------------------------------