Schematic visualization of the inversion process in the space spanned by the MHD-like and atomic-like variables. The background color indicates deviation from the NLTE consistency, ℒ_Λ, for every combination of the MHD- and atomic-like variables, with the brightest color representing the minimum value. The red line shows the common approach to the NLTE inversion as a sequence of physically consistent NLTE models of decreasing χ² value (constrained minimization). The blue line shows an unconstrained minimization with allowed inconsistent solutions during the inversion process.