Function calculate_constraint_violation 

fn calculate_constraint_violation(
    geometry: &Geometry,
    constraint: &Constraint,
) -> f64

Calculates the constraint violation for a single geometric constraint.

This function evaluates how much the current geometry deviates from the target constraint value. The violation is the difference between the current coordinate value and the desired target value.

Mathematical Definition

For a constraint g(x) = target, the violation is:

violation = g(x) - target

Arguments

• geometry - Current molecular geometry
• constraint - The geometric constraint to evaluate

Returns

The constraint violation as a signed value:

• Positive: Current value exceeds target
• Negative: Current value is below target
• Zero: Constraint is perfectly satisfied

Examples

For a bond constraint with target 1.5 Angstrom:

• Current bond = 1.8 Angstrom → violation = +0.3 Angstrom (too long)
• Current bond = 1.2 Angstrom → violation = -0.3 Angstrom (too short)
• Current bond = 1.5 Angstrom → violation = 0.0 Angstrom (satisfied)