Skip to content

Gurobi

What it is

Gurobi is a commercial linear, mixed-integer, and quadratic programming solver used widely on large energy-system optimisation models. FlexTool dispatches to Gurobi through polar-high's adapter; FlexTool itself never imports gurobipy directly and never inspects a licence. Pre-configured gurobipy.Env objects (for example with WLS credentials) can be passed through, but the licence-discovery path is Gurobi's own.

Official site: https://www.gurobi.com/

License options

  • Commercial. Named-user, floating, and machine licences via the Gurobi sales channel.
  • Academic. Free for students, faculty, and staff at recognised degree-granting institutions. Renewable annually from an academic IP.
  • Free trial. Time-limited evaluation licence available from the Gurobi website with vendor sign-off.
  • WLS (Web Licence Service). Cloud-friendly token-based licensing for containers, CI, and shared infrastructure.

Licence acquisition page: https://www.gurobi.com/solutions/licensing/

Installation

Install the Python wrapper:

pip install gurobipy

polar-high also requires scipy for the vectorised matrix load on the Gurobi path; it is normally already present in a FlexTool environment, but if pip install gurobipy complains about a missing dependency, add it:

pip install scipy

After installing the wrapper, set up a licence file. The simplest single-machine path:

  1. Sign in at https://www.gurobi.com/ and request a licence appropriate for your situation (commercial, academic, or trial).
  2. Use Gurobi's grbgetkey tool, or the equivalent web flow, to download a gurobi.lic file.
  3. Place gurobi.lic at either of:
  4. $HOME/gurobi.lic (user-scoped, the simplest), or
  5. /opt/gurobi/gurobi.lic (system-wide), or
  6. any path of your choice, then set the GRB_LICENSE_FILE environment variable to that path.

WLS and Compute Server users typically build a gurobipy.Env programmatically with credentials from the Gurobi web portal; FlexTool's dispatch accepts a pre-built env via the polar-high env= kwarg, but routing one through from a FlexTool scenario is currently a developer-level operation (no Spine parameter for the env object yet).

Verification

After installing gurobipy, run:

python -c "from polar_high.solvers import available_solvers; print(available_solvers)"

Expected: 'gurobi' appears in the printed list:

['gurobi', 'cplex', 'xpress', 'copt', 'highs']

gurobi in the list confirms only that the wrapper is importable — licence discovery still happens at solve time. To check that the licence is also working, point FlexTool at any small Gurobi-targeted scenario and run it; or, outside FlexTool:

python -c "import gurobipy as gp; gp.Model().optimize()"

A clean exit (no GurobiError) means the licence is found.

Common errors

The error messages below are what FlexTool surfaces as FlexToolUserError — they wrap polar-high's exception, which in turn wraps Gurobi's raw GurobiError. The raw vendor text appears in the FlexTool log as the cause of the wrapped exception.

  • No licence file found. Gurobi GurobiError with errno in 10009..10015 (most commonly 10009 "No Gurobi license found"). FlexTool shows: "Solver 'gurobi' is installed but its license check failed. Details: Gurobi license check failed (code 10009): No Gurobi license found. Place gurobi.lic at $HOME or /opt/gurobi/, set GRB_LICENSE_FILE, or pass a configured gurobipy.Env via env=...". Fix by placing the gurobi.lic file or setting GRB_LICENSE_FILE.
  • Licence expired. Same FlexTool message family with the vendor text "License has expired". Renew through the Gurobi web portal.
  • Wrapper installed but scipy missing. FlexTool shows: "Solver 'gurobi' is not installed on this system. ..." with the underlying cause "scipy is not installed (required by the Gurobi adapter for vectorized matrix load)". Run pip install scipy.
  • Unknown Gurobi option. Setting a typo'd key in solver_arguments (e.g. TimeLImit instead of TimeLimit) raises GurobiError from Model.setParam; FlexTool surfaces it as "Solver 'gurobi' returned an error: Gurobi error (code ...): unknown parameter ...". Fix the typo.

How to set it in FlexTool

On the solve entity for the solve you want Gurobi to handle:

solve_advanced.solver         = "gurobi"
solve_advanced.solver_mip_gap = 0.005
solve_advanced.solver_arguments:
  Method     = 2
  Presolve   = 2
  MIPFocus   = 1

flextool <input_db_url> --solver-time-limit 60 --highs-threads 8

The convenience knobs translate to TimeLimit, MIPGap, and Threads respectively. Raw solver_arguments entries pass through untouched and win on any key collision with the convenience knobs.

Verified install on: [empty]