# Introduction¶

*Samplers* are processes that sample from low energy states of a problem’s objective function.
A binary quadratic model (BQM) sampler samples from low energy states in models
such as those defined by an Ising equation or a Quadratic Unconstrained Binary Optimization
(QUBO) problem and returns an iterable of samples, in order of increasing energy. A
dimod sampler provides ‘sample_qubo’ and
‘sample_ising’ methods as well as the generic BQM sampler method.

The `SimulatedAnnealingSampler`

sampler implements the simulated annealing
algorithm, based on the technique of cooling metal from a high temperature to improve its
structure (annealing). This algorithm often finds good solutions to hard optimization problems.