Introduction

POUNCE is a pure-Rust port of the Ipopt interior-point nonlinear programming solver. It solves problems of the form

min  f(x)
s.t. g_L <= g(x) <= g_U
     x_L <=   x  <= x_U

where f and g are twice-continuously-differentiable.

The algorithm, console output, and option semantics follow upstream Ipopt closely enough that anyone used to reading ipopt logs can drop in pounce without relearning where the numbers live.

Pure Rust by default

The default build is pure Rust — no Fortran, no commercial solver, no system BLAS required. The bundled FERAL backend provides a sparse symmetric LDLᵀ factorization. The HSL MA57 backend is available behind the optional ma57 feature for users who have a license for libcoinhsl and have it installed (see Installation).

Status

Production-ready for the core IPM workflow. The algorithm-side core, NLP interface, line search, filter, barrier update (monotone + Mehrotra adaptive), KKT solve, restoration phase, AMPL .nl reader, the C ABI (pounce-cinterface), the Python wrapper (pounce-solver), and the CLI all solve a wide range of NLPs from the standard test suites (Hock-Schittkowski, CUTEst, Mittelmann ampl-nlp, CHO parameter estimation, gas/water network design). Sensitivity analysis (sIPOPT port), reduced-Hessian computation, the auxiliary-equality + FBBT presolve, and the active-set SQP path are all wired in and available behind option keys. Existing PyIpopt / cyipopt / JuMP / AMPL clients link against libpounce_cinterface in place of libipopt unchanged.

License

EPL-2.0, the same license as upstream Ipopt.

Where to go next

• Installation — build and install POUNCE.
• Quick Start — solve your first problem.
• Running Solves — the command-line driver in depth.
• Acknowledgments — the papers behind the algorithm.