Function einstein_tensor_kernel 

pub fn einstein_tensor_kernel<T>(
    ricci: &CausalTensor<T>,
    scalar: T,
    metric: &CausalTensor<T>,
) -> Result<CausalTensor<T>, PhysicsError>
where
    T: Field + Float + From<f64>,

Calculates the Einstein Tensor: $G_{\mu\nu} = R_{\mu\nu} - \frac{1}{2} R g_{\mu\nu}$.

Arguments

• ricci - Ricci curvature tensor $R_{\mu\nu}$ (Rank 2).
• scalar_r - Ricci scalar $R$.
• metric - Metric tensor $g_{\mu\nu}$ (Rank 2).

Returns

• Ok(CausalTensor<T>) - Einstein tensor $G_{\mu\nu}$.