- `FactorFile` will keep an ordered reversed list with the dates.
Calling `Reverse()` on the `SortedList` is expensive.
- `MapFiles` will keep first and last date, so we don't need to call
`First()` and `Last()` multiple times.
- `Liquidate` will go through all the algorithms securities only if
necessary
- `TradeBar` parsing will not call `new T` for pure `TradeBar` which is
expensive
- Removing `Lazy` hash code and security type for the
`SecurityIdentifier`, replacing for direct initialization. Accessing the
`Lazy` value adds an overhead.
- Replacing `Enum` to string for hardcoded switch statement. `Enum.ToString` is expensive.
- `DataManager` will be lazy for counting the subscriptions for
determining if its above the limit
- Adding `AlgorithmSecurityValuesProvider.GetAllValues()`, removes the
need to fetch all the security keys twice.
- During universe selection, will not try to re add already added symbol
- Using `Aggregate(lambda)` vs `Sum(lambda)` since the later is slower
due to performing an extra `Select`
- For `QCAlgorithm.Framework.OnFrameworkData()` will avoid calling
`ToArray()` on empty `Enumerables` due to its cost * the number of
calls. If the `Enumerable` is the empty instance, which is static,
will create a new empty array and return it instead.
- Replacing `SecurityIdentifier` `SecurityType` and `GetHashCode`
implementations for `Lazy` versions, that are performed just once, since
these values do not change and are used multiple times.
- For the different `DataDictionary<T>` implementations adding `this[
Symbol] get; set` since existing overload `this [string]` produces an
extra round operations `Symbol->string->Symbol` with a significant
impact.
- Adding `PortfolioTargetCollection.AddRange()` overload using an array
to avoid unnecessary convertions.
The term 'alpha' is used to describe the entire algorithm. Therefore, 'alpha'
produces insights. From this we have things like IAlphaModel, which is the model
defining how insights are produced. We have IAlphaHandler, which defines how the
insights from a single 'alpha' (the algorithm) are managed, analyzed, and stored.
Types closer to the individual prediction level, such as InsightDirection, or
InsightScore relate directly to exactly 1 insight. The distinction between the
two became more clear as we developed the insights API, and from that effort it
was decided to harmonize alpha/insight terminology across the various QC systems.
The IAlphaManagerExtension defines a type that needs to react to events produced
by the AlphaManager. The actual events were removed in favor of a interface to
handle the events. This removes the need to wire events and instead just pass the
extensions to the alph manager and it will handle invoking the extensions at the
appropriate time.
This change removes all charting and statistics aggregation logic from the alpha
handler and moves it into dedicated types, AlphaChartingManagerExtension and
AlphaStatisticsManagerExtension. The resulting types are highly decoupled from the
LEAN ecosystem allowing them to be easily unit tested, whereas before the logic
was embedded in a handler with many many dependencies which would be very hard to
properly unit test.
As part of this change (and in preparation for moving scoring to the alpha thread)
the resolution of SecurityValues was removed from the alpha manager. In this new
pattern, the alpha manager is pushed generated alphas and security values at each
time step.
Martin Molinero