Results of the product between reconstruction matrix in diffraction limited condition and SIMPC for seeing of 1.4 arcsec, without modulation and with sub-aperture size of 0.2 m. This is the so called modal optical gain matrix. An absolute value is used and only the first 100 × 100 elements of the matrix is shown for clarity reasons. It can be easily seen that that the matrix is not diagonal. The diagonal of this matrix is shown in Fig. 7 (orange solid line). Refers to the 8 m-class telescope case.