Is there a simple library for (simple) numerical optimisation in clojure? I’m thinking something like R’s optim or scipy.optimize.minimize

I know incanter has a similar function, is there anything else out there?

that's a tricky question because optimization is (almost) never a simple problem. otherwise, the no free lunch theorem would not exist. since there is no default optimization algorithm (other than in toy settings) to find the answer to that question, you'd first need to tell what you are trying to optimize.

Apache commons math and weka have good selection of optimization functions. Maybe there you can find what you want.