GRG Non Linear Solver Equivalent

I am looking to use Math.NET to implement the excel GRG Non Linear solver in C#. This seems to fall under the non linear optimization topic in Math.NET and I was able to find a few examples of optimization in https://github.com/mathnet/mathnet-numerics/tree/master/src/Numerics.Tests/OptimizationTests

It wasn’t clear to me if I could use this Optimization package to implement a non-linear optimization algorithm where I can supply the function (to be minimized) and the constraint function as matrices, in addition to bound constraints on the variables.

Could someone knowledgeable please clarify this point for me?

I don’t know exactly what you are looking for, but have a look here. This appears to be a variety of conjugate gradient solver.