Trunc
Truncation or trunc is a mathematical term that appears frequently in GemStone IV equations that do everything from figuring out a character's mana point total to how many premium points it costs to enchant an item.
To truncate a number, remove all decimal places after the whole number (integer) without rounding. Thus, 6.1 and 6.9 would both be 6 when truncated.
Example
Total premium points required for enchanting plain item (+5 added) with a starting enchant bonus of +16 to +45:
- 1200 + (400 * trunc((current plus - 11) / 5)))
For this example we'll use a "current plus" of 20 (the item is standard 4x enchanted).
- 1200 + (400 * trunc((20 - 11) / 5))) = 1200 + (400 * trunc(9/5)) = 1200 + (400 * trunc(1.8)) = 1200 + (400 * 1) = 1200 + 400 = 1600
"Trunc to 0.xx"
In some formulas, instead of truncating to a whole number, values may be truncated to n digits after the decimal point. In mathematical terms this is the trunc(x, n) function. On the wiki this may also be described as "trunc to 0.XX" for 2 digits, etc.
Wiki Expressions
GSWiki supports inline expression parsing using trunc.
{{#expr: trunc(1.234)}}produces 1{{#expr: trunc(1.234 * 100) / 100}}produces 1.23
References
- Truncation on Wikipedia