Function regular_integration_fixed_order 

pub fn regular_integration_fixed_order(
    source_point: &Array1<f64>,
    source_normal: &Array1<f64>,
    element_coords: &Array2<f64>,
    element_type: ElementType,
    physics: &PhysicsParams,
    gauss_order: usize,
) -> IntegrationResult

Compute element integration with fixed quadrature order (no adaptation)

This is a simpler version for far-field elements where adaptation is not needed.