Metrics

New in version 1.15.0

Metrics are special kinds of sorter adapters that can be used to compute properties about a sorting algorithm, such as the number of comparisons performed while sorting a given collection, or the time it took to sort. As sorter adapters, metrics follow the unified sorting interface, and do sort the passed collection before returning the result.

The anatomy of a metric adapter is thus close to that of any sorter adapter with the following additional properties:

• The result of the adapted sorter's is replaced with an instance of cppsort:::utility::metric, which is a small wrapper type encapsulating a value.
• It exposes a tag_t aliasing the tag of the returned metric value.
• It exposes a metric_t type aliasing the returned metric type.

The metrics tag can be any type, generally ending with the _tag suffix, and can be either empty or contain freeform static metadata about the kind of metric that uses it. Future versions of cpp-sort might standardize some tag fields.

Available metrics

All available metrics live in the subnamespace cppsort::metrics. Even though all of them are available in their own standalone header, it is possible to include all of them at once with the following include:

#include <cpp-sort/metrics.h>

All of the metrics headers also includes <cpp-sort/utility/metrics_tools.h>.

comparisons

#include <cpp-sort/metrics/comparisons.h>

Computes the number of comparisons performed by the adapted sorter.

This is done by wrapping the passed comparison function. As such it only works with sorters that accept a comparison, and bypasses components that special-case specific comparison objects.

template<
    typename Sorter,
    typename CountType = std::size_t
>
struct comparisons;

Returns an instance of utility::metric<CountType, comparisons_tag>.

projections

#include <cpp-sort/metrics/projections.h>

Computes the number of projections performed by the adapted sorter.

This is done by wrapping the passed projection function. As such it only works with sorters that accept a projection, and bypasses components that special-case specific projection objects.

template<
    typename Sorter,
    typename CountType = std::size_t
>
struct projections;

Returns an instance of utility::metric<CountType, projections_tag>.

running_time

#include <cpp-sort/metrics/running_time.h>

Computes the time it takes for the adapted sorter to sort a collection, using a steady clock by default.

template<
    typename Sorter,
    typename DurationType = typename std::chrono::steady_clock::duration
>
struct running_time;

Returns an instance of utility::metric<DurationType, running_type_tag>.