[BUG] [python] Python API errors when solving LP with no constraint

[mtanneau]

Describe the bug

Attempting to solve a linear program with no constraints (other than variable bounds) results in an error.

Steps/Code to reproduce bug

from cuopt.linear_programming.problem import Problem, CONTINUOUS, MINIMIZE
from cuopt.linear_programming.solver_settings import SolverSettings

problem = Problem("no_constraints")
x = problem.addVariable(lb=0.0, vtype=CONTINUOUS, name="x")

problem.setObjective(x, sense=MINIMIZE)

settings = SolverSettings()

# This will error
problem.solve(settings)

on my machine, this produces the following log (note the first line)

Error in solve_lp: {"CUOPT_ERROR_TYPE": "ValidationError", "msg": "A_offsets must be set before calling the solver."}
cuOpt version: 26.2.0, git hash: f73da24d, host arch: aarch64, device archs: 75-real,80-real,86-real,90a-real,100f-real,120a-real,120
CPU: Unknown, threads (physical/logical): 1/20, RAM: 108.74 GiB
CUDA 13.1, device: NVIDIA GB10 (ID 0), VRAM: 119.70 GiB
CUDA device UUID: 43bce240-d7d6-65e5-ca7a-e351bab5de7a

Expected behavior

The problem should be passed to the solver and solved correctly.

Environment details (please complete the following information):

• Environment location: DGX Spark workstation
• Method of cuOpt install: via pip in a python virtual environment. I am using cuopt v26.02 release.

Additional context

I tried this with a quadratic term in the objective, and obtained the same error.

[chris-maes]

We don't currently support LP or QPs with no constraints.

[chris-maes]

We will try to add support for this in an upcoming version.