How to implement the cost function?

Hi, Can anyone help me understand how to implement the cost function: u = arg min(||g-u||).^2 + lambda.R(u) where the term "(||g-u||).^2" is the data fidelity term between the original clean image and the noisy image R(u) is a regularization parameter. Thanks in advance

[Anika]

I have same doubt. Can you please help me with this.