1 .. index:: single: Blue (example)
3 This example describes the interpolation between two physical states. These two
4 vector fields, of identical discretization, are the observation
5 :math:`\mathbf{y}^o` and the background state :math:`\mathbf{x}^b`. The
6 confidence in errors on the two information are considered identical. The
7 :math:`H` model fully observe the available field, it is a matrix selection