Attribute Macro auto_jacobian 

#[auto_jacobian]

Attribute macro that generates a jacobian method from a residual method.

Apply this to an impl block containing a method marked with #[residual]. The macro will parse the residual expression and generate the corresponding Jacobian computation using symbolic differentiation.

Attributes

• #[jacobian(array_param = "x")] - Name of the state vector parameter (default: “x”)

Example

#[auto_jacobian(array_param = "x")]
impl MyConstraint {
    #[residual]
    fn residual(&self, x: &[f64]) -> f64 {
        x[0] * x[0] + x[1] * x[1] - 1.0  // Unit circle constraint
    }
}

// Generates:
// fn jacobian_entries(&self, x: &[f64]) -> Vec<(usize, usize, f64)> {
//     vec![
//         (0, 0, 2.0 * x[0]),  // d/dx[0]
//         (0, 1, 2.0 * x[1]),  // d/dx[1]
//     ]
// }