unitaria.Estimator

class unitaria.Estimator(default_precision: float, default_failure_probability: float = 0.01)[source]

Bases: ABC

Interface representing a way to estimate the norm of a block encoding.

Parameters:

  • default_precision – Default for the precision parameter in estimate_norm.

  • default_failure_probability – Default for the failure_probability parameter in estimate_norm.

abstractmethod estimate_norm(precision: float | None = None, failure_probability: float | None = None) → float[source]

Estimate the norm of the given block encoding.

The block encoding must represent a vector. The returned value is guaranteed to lie in the range [0, node.normalization].

The implementors of this method are free to interpret the precision``argument loosely, and ignore the ``failure_probability argument.

Parameters:

  • node – The node representing the vector of which to compute the norm.

  • precision – The absolute precision, with which the norm should be computed. If None, self.default_precision is used instead.

  • failure_probability – The maximum allowed failure probability, with which the absolute error of the estimate may exceed the given precision. If None, self.default_failure_probability is used instead.