Restate Subtraction

import mathy_core.rules.restate_subtraction

Subtraction operations aren't commutable, but addition of negative values are. This flips a subtraction to a plus negation, to "unlock" terms and allow moving them around, e.g. for like-terms simplification.

Examples¶

Info

All the examples shown below are drawn from the mathy test suite that verifies the expected input/output combinations for rule transformations.

Input	Output	Valid
-9 = -10 - -h	-9 = -10 + h	✔
-7 - -4 = -t	-7 + 4 = -t	✔
m - 3 = 3	m + -3 = 3	✔
3u^2 - -1t^4 + -u^2	3u^2 + 1t^4 + -u^2	✔
-4x^3 - -2x^3	-4x^3 + 2x^3	✔
4x - -2x	4x + 2x	✔
m^2 - (3m^2 - 12m^2 - g^2)	m^2 + -(3m^2 - 12m^2 - g^2)	✔
2x - 9	2x + -9	✔
2x - 9x	2x + -9x	✔
2x - 9x^3	2x + -9x^3	✔
2x + -9	2x - 9	✔
2x + -9x	2x - 9x	✔
2x + -9x^3	2x - 9x^3	✔
4 - 3x	4 + -3x	✔

API¶

RestateSubtractionRule¶

RestateSubtractionRule(self, args, kwargs)

Convert subtract operators to plus negative to allow commuting

get_type¶

RestateSubtractionRule.get_type(
    self, 
    node: mathy_core.expressions.MathExpression, 
) -> Optional[str]

Determine the configuration of the tree for this transformation.

Support two types of tree configurations: - Subtraction is a subtract to be restate as a plus negation - PlusNegative is a plus negative const to be restated as subtraction