Generalisation of parameter methods and D decomposition

The parameter methods, namely the parameter-plane and the parameter-matrix formulations, were developed to solve high-order multiloop distributed-parameter problems that were too tedious to be solved using the usual classical techniques. Essentially, the methods give graphical plots relating two design parameters and the zeros of the characteristic equation. The paper summarises the solution for several previously obtained cases relating the parameters and coefficients, and generalises the relationship to a completely unrestricted case, using well known function-minimisation methods, such as the conjugate-gradient technique. Moreover, a useful comparison to the generalised D decomposition method is made.