ausboss-ComfyUI-AusBoss/js/docs/AUSBOSS_NODES_MathExpression.md

Math Expression

Evaluates one arithmetic expression over the inputs a, b and c and returns the result as both FLOAT and INT — width and height math, strength ramps, frame counts.

Controls

• expression: The arithmetic to evaluate. Allowed: numbers, the names a/b/c, the operators + - * / // % **, parentheses, unary minus, and the functions min, max, abs, round, floor, ceil, sqrt. Examples: a * 2, floor(a / 64) * 64, min(a, b) + 0.5, sqrt(a*a + b*b).
• a, b, c: The values the expression reads, as three sockets on the node's left edge that take a FLOAT or an INT. An unwired one reads as 0, and an unused one costs nothing; a constant belongs in the expression itself (a * 2, floor(a / 64) * 64).

Outputs

• float: The result as a float.
• int: The result rounded to the nearest whole number; halves round away from zero (2.5 becomes 3, -2.5 becomes -3).

Safety

The expression is parsed with Python's ast module and walked against a whitelist — it is never passed to eval. Anything outside the grammar above (other names, attribute access, subscripts, strings, comparisons) stops the run with an error naming what to remove, so a workflow shared by someone else cannot smuggle code through this node. Division by zero and overflowing results are clear errors rather than a crash or an inf traveling downstream.