ApplicationError: No executable found for solver 'cbc'

[david26694]

Summary

Steps to reproduce the issue

$ which cbc
$ python example.py

# example.py
from pyomo.environ import *

# Create a model
model = ConcreteModel()

# Define variables (x, y >= 0)
model.x = Var(within=NonNegativeReals)
model.y = Var(within=NonNegativeReals)

# Define objective function (Maximize Z = 3x + 5y)
model.objective = Objective(expr=3 * model.x + 5 * model.y, sense=maximize)

# Define constraints
model.constraint1 = Constraint(expr=2 * model.x + 3 * model.y <= 12)
model.constraint2 = Constraint(expr=model.x + model.y <= 5)

# Solve the model using CBC
solver = SolverFactory('cbc')
result = solver.solve(model)

# Display results
model.display()

Error Message

$ ApplicationError: No executable found for solver 'cbc'

Information on your system

Pyomo version: Pyomo 6.8.2
Python version: 3.12.7
Operating system: macos sequoia, version 15.2
How Pyomo was installed (PyPI, conda, source): poetry
Solver (if applicable): cbc

Additional information

I also get False in here:

from pyomo.environ import SolverFactory

print("Available solvers:")
print(SolverFactory('cbc').available(exception_flag=False))  # Should return True
print(SolverFactory('ipopt').available(exception_flag=False))  # Should return True

but I run which cbc in terminal and it returns /usr/local/bin/cbc. I have also got this error during a .solve:

-> [2274](https://file+.vscode-resource.vscode-cdn.net/Users/davidmasip/Documents/Workspace/pricing-data/dynamic_pricing/notebooks/~/Documents/Workspace/pricing-data/dynamic_pricing/.venv/lib/python3.12/site-packages/pyomo/contrib/mindtpy/algorithm_base_class.py:2274)     raise ValueError(self.config.mip_solver + ' is not available.')
   [2275](https://file+.vscode-resource.vscode-cdn.net/Users/davidmasip/Documents/Workspace/pricing-data/dynamic_pricing/notebooks/~/Documents/Workspace/pricing-data/dynamic_pricing/.venv/lib/python3.12/site-packages/pyomo/contrib/mindtpy/algorithm_base_class.py:2275) if not self.mip_opt.license_is_valid():
   [2276](https://file+.vscode-resource.vscode-cdn.net/Users/davidmasip/Documents/Workspace/pricing-data/dynamic_pricing/notebooks/~/Documents/Workspace/pricing-data/dynamic_pricing/.venv/lib/python3.12/site-packages/pyomo/contrib/mindtpy/algorithm_base_class.py:2276)     raise ValueError(self.config.mip_solver + ' is not licensed.')

ValueError: cbc is not available.

[jsiirola]

This looks like you are not running from a command line and instead are running from within vscode. Most likely, your vscode environment (particularly the PATH) doesn't match the environment you are using in a terminal. Fixing that should resolve your problem.

Alternatively, you can manually set the path to CBC with:

from pyomo.common import Executable
Executable('cbc').set_path('/usr/local/bin/cbc')