Usage Guide

1. Write an expression you would like to evaluate to the input box
2. Click Simulate (Hotkey = S)

Binary Operators (combine two values)

• d - Dice roll: NdS rolls N dice with S sides
• Has the highest precedence
• + - Addition
• - - Subtraction
• * - Multiplication
• / - Division
• > - Greater than (returns 1 if true, 0 if false)
• < - Less than (returns 1 if true, 0 if false)
• >= - Greater than or equal (returns 1 if true, 0 if false)
• <= - Less than or equal (returns 1 if true, 0 if false)
• == - Equal (returns 1 if true, 0 if false)
• != - Not equal (returns 1 if true, 0 if false)
• max - Maximum: takes the maximum of two values (e.g for Advantage)
• min - Minimum: takes the minimum of two values (e.g. for Disadvantage)
• reroll - Reroll unmodified values and take the new result. Supports ranges as the left operand.
  • Syntax: [dice roll] reroll [number or range]
  • Has the second highest precedence
  • Examples:
    • 2d6 reroll 1 - Roll two d6 dice, and for each die, reroll a result of 1.
    • 2d6 reroll 1:2 - Re-rolls results of 1 and 2
    • 2d6 reroll i:j - Roll two d6 dice, and for each die, reroll a result of i up to j (inclusive)
• repeat - Repeat a computation n times, sum the results
  • Syntax [expression] repeat [n_repetitions]
  • Has the lowest precedence
  • Example: (d20 + 5 >= 15) * (2d6 + 3) repeat 2 - Two attacks with the same modifers

Unary Operators (apply to one value)

• - - Negation (multiply by -1)

Examples

• Roll a 20-sided die
  • d20
• Roll two 6-sided dice and add 5
  • 2d6 + 5
• Roll d20 with advantage and add 5
  • d20 max d20 + 5
• Check if d20 roll is 15 or higher (1 for success, 0 for failure)
  • (d20 >= 15)
• Attack roll (d20) with advantage, with attack bonus + 5, against AC 15, causing 2d6 + 5 damage on hit.
  • (d20 max d20 + 5 >= 15) * (2d6 + 5)
• Two attack rolls, both against the same AC and with the same attack bonuses, but with different damage values.
  • (d20 + 5 >= 15) * (2d6 + 5) + (d20 + 5 >= 15) * (1d4 + 5)
• Comparison between attacks with Heavy Weapon Master(HWM) and without. n is the base attack bonus, and k is the AC. The median matrix will have 1 on the positions where the HWM attack deals more damage on average. Use variables to set different values for n and k.
  • ((d20 max d20 + n - 5 >= k) * (2d6 + 5 + 10)) > ((d20 max d20 + n >= k) * (2d6 + 5 ))

Variables

Allow you to evalute the expression for multiple values at the same time.

Each variable has - Name - string that you can write inside the expression - Value - set of values that the variable can have.

Inside the dice expression, each instance of name will be substituted for one value from the set (each instance of variable x will get the same value assignment in a single experiment), and then the experiment is run. We test every possible combination of value assignments and then report the results in a table.

Example

For example, we would like to see how much damage we can do against multiple AC variants at the same time. Our attack and damage rolls looks like

# Attack roll
d20 + 7 + d4

# Damage roll
2d6 + 4

We have - +7 attack bonus - Buff that adds 1d4 to our hit rolls - We deal 2d6 + 4 damage on hit

We want to see how we fare against foes with some reasonable AC values, e.g. $\text{AC} \in \set{10, 11, ... , 20}$. We can use a variable for the AC. 1. Click on the Add Variable button 2. Set name to AC 3. Set values to 10-20

Now we can write a dice expression using the variable.

(d20 + 7 + d4 >= AC) * (2d6 + 4)

Now, when we press Simulate, we will run many experiments, substituting AC in the expression for each possible value in the value set of the variable AC. In the summary column, we will get a table with the results, one row for each value of AC.

If we would like to evaluate multiple attack bonuses, we can use another variable, e.g. n with values set to 5-9, and rewrite the expression to

(d20 + n + d4 >= AC) * (2d6 + 4)