# Using a Classical Solver¶

You might use a classical solver while developing your code or on a small version of your problem to verify your code. To solve a problem classically on your local machine, you configure a classical solver, either one of those included in the Ocean tools or your own.

## Examples¶

Among several samplers provided in the dimod
tool for testing your code locally, is the `ExactSolver()`

that calculates the energy of all
possible samples for a given problem. This example solves a two-variable Ising model
classically on your local machine.

```
>>> import dimod
>>> solver = dimod.ExactSolver()
>>> response = solver.sample_ising({'a': -0.5, 'b': 1.0}, {('a', 'b'): -1})
>>> response.data_vectors['energy']
array([-1.5, -0.5, -0.5, 2.5])
```

This example solves the previous problem using the dwave_neal simulated annealing sampler. The two samples requested and generated by this classical solver on your local machine vary by execution.

```
>>> import neal
>>> solver = neal.SimulatedAnnealingSampler()
>>> response = solver.sample_ising({'a': -0.5, 'b': 1.0}, {('a', 'b'): -1}, num_reads=2)
>>> response.data_vectors['energy']
array([-1.5, -0.5])
```