linear_struct_backward.rs

/// Perform backward pass through the linear layer.
fn backward(&mut self, dL_dy: &Array2<f64>) -> Array2<f64> {
    // Calculate the gradient of the loss with respect to W
    let dL_dW = dL_dy.t().dot(
        &self
            .dy_dW
            .as_ref()
            .expect("Need to call forward() first.")
            .view(),
    );

    // Calculate the gradient of the loss with respect to b
    let dL_db = dL_dy.t().dot(&Array2::ones((dL_dy.shape()[0], 1)));

    // Store the gradients for later use
    self.dL_dW = Some(dL_dW);
    self.dL_db = Some(dL_db.to_owned());

    // Calculate the gradient of the loss with respect to the input


    dL_dy.dot(&self.W)
}