1. A method of adjusting the homogeneity correctors of the magnetic field created by a magnet, including the following phases: the real field created by the magnet is measured, the analytic expression of the measured real field is calculated over a base of N orthogonal functions, this analytic expression being expanded as a summation of N orthogonal components each component being the result of the multiplication of one of said orthogonal function by a specific coefficient, the number of these specific coefficients being equal to N, said N specific coefficients representing said real field, the analytic expressions of fields produced by N correction means as a function of their adjustment state are calculated in a same manner over the same base, the analytic expression of an ideal field to be obtained with the magnet is calculated in a same manner over the same base, an algebraic combination is made of the analytic expressions of the correction fields so as to make it equal, and of opposite sign, to the difference of the analytic expressions of the real and ideal fields, said algebraic combination comprising a step of giving a solution to a system of N equations related to the N orthogonal functions, with N unknowns, said N unknowns being each in correspondence to a particular correction means of said N correction means, and the N correction mean are adjusted as a function of the results of this algebraic combination.