Ask HN: What interesting problems are you working on?
1.)  A solver for the unstructured Euler equations.  ...I was intending to volunteer time for an local university project investigating parallels between Holographic light with orbital angular momentum and hydrodynamics (in this case the Euler&#x2F;Madelung equations).  Not sure what happened as... volunteers get lost in the shuffle?  Anyway, the solver is fun.<p>2.)  Porting my Python code for nonlinear gradient driven optimization of parametric surfaces to C++.  Includes a constraint (propagation) solver based on Minikanren extended with interval arithmetic for continuous data (interval branch and contract).  This piece is a pre-processor, narrowing the design space to only feasible hyper-boxes before feeding design parameter sets (points in design space) to the (real valued) solver.  Also it does automatic differentiation of  control points (i.e. B-spline control points) so I can write an energy functional for a smooth surface, with Lagrange multipliers for constraints (B-spline properties).  Then I get the gradient and Hessian without extra programming.  This makes for plug and play shape control.  I am looking to extend this to subdivision surfaces and&#x2F;or to work it towards mesh deformation with discrete differential geometry so I&#x27;ve been baking with those things in separate mini-projects.<p>3.)  Starting the Coursera discrete optimization course.  This should help with, e.g. knapsack problems on Leetcode, some structural optimization things at work, and also it seems the job market for optimization is focused on discrete&#x2F;integer&#x2F;combinatorial stuff presently so this may help in ways I do not foresee.<p>4.)  C++ expression template to CUDA for physical simulation:  I am periodically whittling away at this.