On diagonally structured scheme for nonlinear least squares and data-fitting problems Mahmoud Muhammad Yahaya, Poom Kumam, Parin Chaipunya, Aliyu Muhammed Awwal and Lin Wang RAIRO-Oper. Res., 58 4 (2024) 2887-2905 Published online: 31 July 2024 DOI: 10.1051/ro/2024102