Search Methods

ANS includes several different Search Methods for finding the best sizing solution. Some methods are very similar, while others are entirely unique, and each is particularly suited to certain kinds of mathematical problems.

It is impossible to state that one method is always better or worse than another. The quality and speed of each method depends on the specific system being solved and the sizing input. A method that excels for one model may not be the best choice for another model.

Note: All of the methods share a common goal of minimizing (or maximizing) an Objective. The analytical approach driving the sizing (the hydraulic solver) does not vary with the selected method. This means that the best sizing solution across all of the methods is the best overall solution. It is good practice to test several of these methods for any model.

• Modified Method of Feasible Directions - Reliable and applicable to most problems.

• Sequential Quadratic Programming - Frequently the most efficient, but more sensitive to system definition.

• Sequential Unconstrained - Sensitive to initial sizes and control parameters, but more capable of handling large numbers of uniquely sized pipes.

• Genetic Algorithm - Cross-breeds a random "population" of designs, mimicking biological evolution. Less likely to become trapped in a local minimum, but very slow compared to other methods.