[IDEA] Problem Formulation

[light-weaver]

• What is the current behavior? Problems are formulated using the MOProblem class.

• Describe the solution you'd like Problem formulations should be represented as JSON objects. They can be read into Python as Dataclasses and stored in databases without changes. This requires analytical formulations of objectives to be stored as MathJSON objects instead of Numpy expressions. The MathJSON objects can be converted to Polars expression for evaluation with currently implemented methods. Alternatively, we can implement other converters that convert the problem formulation to, for example, numpy/pandas expressions, PuLP expressions, Gurobipy expression. We can even convert the MathJSON objects to industry-standard file formats (only for single objective optimization. Yan's work is the first step towards this idea.

• What is the motivation/use case for changing the behavior? Currently, arbitrary python objects have to be stored into the database. This is bad behaviour and prevents complicated use cases such as updating/changing problem formulation.

• Additional context Insight into how to handle surrogate modelling, external simulators, arbitrary binaries, and scenario based optimization needs further discussion.