Instead of having separate ExchangeCalendar and TradingSchedule objects, we
now just have TradingCalendar. The TradingCalendar keeps track of each
session (defined as a contiguous set of minutes between an open and a close).
It's also responsible for handling the grouping logic of any given minute
to its containing session, or the next/previous session if it's not a market
minute for the given calendar.
Previously, whenever we try to access a missing value on the Positions
dict, we return a default Position and save it to the dict. Instead,
just return the Position
In preparation for the incoming changes which no longer push every bar
through the tradesimulation, remove the adjustment of the period's cash on
every pricing change of a held futures asset.
Instead hold the last sale price for each held future either:
- At the end of each peformance period update the last sale prices of
all held futures, so that the pnl for the next period uses values
derived from the cash difference between the end of the two periods.
- When a transaction is processed for the Future, so that the correct
amount is applied to each cash adjustment. (i.e. the cash adjustment
is reset on every change of amount of the Future being held, so that
multiple size and prices do not need to be tracked for the same asset.)
Also, remove now unused dict of payout calculation modifier, since new
calculation reads the value directly off of the asset.
Remove update_last_sale test, since the method no longer returns a cash
value.
Instead of calling a function, where the only parameter is the tracker
object, make it a method, so that the snapshot of position tracker stats
can be more easily called as `pt.stats()`.
In preparation for removal of widespread events, change the split
methods to use params for sid and cost, instead of an event, for
compatibility with lazy branch.
co-author: @jbredeche <jean@quantopian.com>
In preparation for removal of widespread events, change the commission
methods to use params for sid and cost, instead of an event, for
compatibility with lazy branch.
co-author: @jbredeche <jean@quantopian.com>
- Combine the net value and exposure functions into `calc_net` since
they use the same logic.
- Change the logic to handle on empty list to using the a start value of
0.0. More concise, and reduces the number of return points from the
function to one.
Instead of calculating the position values for each stat result, e.g.
gross_exposure, net_liquidity etc.; get the positions upfront and then
calculate the period and position stats in order, passing each value
explicitly to the ones that follow it in the dependency chain.
e.g. the gross_value depends on the long_value and the short_value,
which called the position_values property for calculating both the
long_value and the short_value.
Removing the repeated calls to position_values (and
position_exposures) removes the need for the caching the last sale
prices and position amounts in separate vectors, since it is inexpensive
enough to read those values off of the positions dictionary held in the
position tracker.
This patch gives a small gain to ~500 sized portfolios, but the main
intent is to clear the path to not storing last_sale_prices on the
position objects at all. Removing all of the caching layer in this class
makes that change easier to apply. Removing the extra calls to
position_values also made this class easier to step through/reason about
when splicing in the new last sale price access, as well.
This commit removes the ability to reference a shared TradingEnvironment through the zipline.finance.trading module. In place, the classes that require a TradingEnvironment, or its child AssetFinder, contain their own references to those objects.
This commit also adds serialization utilities that allow for the pickling/unpickling of objects without unintentionally their TradingEnvironments or AssetFinders.
on the number of per-tick update that occur since they were duplicated
per each PerformancePeriod. Also opens up the path to cythonizing the
entire object
Jean Bredeche