So that calculations that leverage the range of the treasury_curves,
like `pd.Series.searchsorted` will not overshoot the 'end' of the
range we are calculating risk metrics.
The treasury_duration member in RiskMetrics is never used except
for in unit tests.
Remove the saving of treasury_duration in preparation for the
move of the choose_treasury method out of the RiskMetrics classes.
Down the line, if we do restore the sanving of treasury_duration,
choose_treasury can return a tuple that includes treasury_duration
instead of just returning the rate.
To make the risk metrics being calculated more clear, change the
naming convention that ratios have a '_risk' suffix.
Also, fixes typo in beta docstring.
Move the risk metric definitions to functions at the module level
with defined parameters.
Both risk implementations call these functions, where the difference
between risk implementations is with which internal data they
send to the various risk metrics.
Metrics moved:
- Sharpe Ratio
- Sortino Ratio
- Information Ration
- Alpha
Following the lead of the RiskMetricsBatch conversion to use
more pandas and numpy.
Bringing the iterative and batch versions closer together as we
work towards folding them into one.
So that the environments' exchange time is used without having to
specify it independently.
Also, moves uses of Delorean.shift for the exchange conversion inside
of environment to use the exchange_dt_to_utc method.
Wires up performance tracker so that when `emission_rate` is set
to `minute`, the performance packets are sent out every minute,
instead of once per day.
Please note, the performance packets that are generated are not
ready for prime time consumption, this patch is merely a step towards
hooking up the ability to inspect minute data.
Known issues:
- The packets do not currently include risk information.
Since we need to consider how this affects the denominators
of the risk calculations.
So that Transaction object behavior is exercised, uses the Transaction
object in performance module tests instead of ndict.
Also, adds fields to the __init__ of Transaction, to make the
definition of the object more well defined.
Slight refactoring of grouping the tracking variables in the
PerformanceTracker together.
So that it's easier to see which are config members and which are
members used to track internal state.
- perf modified to let non-performance related events flow through.
- changes to support streaming non-trading data through batch transforms
and for mixing in sids with just custom data.
- allowing CUSTOM events to flow through to transforms.
- Added logic to maintain pre-specified sid filter.
Instead of using division of the amount by itself to extract
the direction, uses math's copysign.
Should be almost functionally equivalent,
but copysign won't have a possible floating point error leading
the direction to not be exactly 1.
So that both computational and memory overhead is reduced,
this turns off serializing positions for cumulative performance.
Positions were essentially being doubled up by being stored
in both cumalative and daily.
So that transactions are kept by default.
This prepares for the addition of the serialize flag added by
@fawce.
Setting the default to True, so that the flags will be aligned.
- added LSE reference rrules calendar (thanks to Edward Johns)
- added tests to verify LSE environment matches rrule calendar
- added a test to verify global environment behavior can be set.
- moved DailyReturn class to trading to eliminate circularity from
risk <-> trading.
- updated TradingEnvironment to be a context manager. This allows users
to run algorithms in individually isolated environments in one python
process. This is useful for managing multiple algorithms in a single
ipython notebook.
- added comments to explain behavior and useage of the global environment
Global state for the financial simulation environment is accessed through the
zipline.finance.trading module, which now contains a module variable:
environment.
Parameters are passed into an algorithm as a keyword argument, sim_params.
SimulationParameters creates a trading day index for the test period that
can be used to find trading days, calculate distance between trading days,
and other common operations. The sim params index is just selected from the
global state.
================
Details:
- adding delorean to the requirements.
- made index symbol a parameter for loading the benchmark data. changed
messagepack storage to be symbol specific.
- ported risk, performance, algorithm, transforms, batch transforms
and associated tests to use simulation parameters and global environment
- factory and sim factory use global state and sim params
- factory method parameter names now reflect the class expected
With this patch, on the close of markets we "fast forward" to midnight of the
next trading day and calculate the dividend payments. This patch assumes that
the dividend dates are all at midnight UTC.
Algorithm returns and the risk calculations that depend on them now include
cash dividends. This commit does _not_ provide an API for user algorithms to
access dividends.
PerformanceTracker expects the dividend data to arrive as events, similar to
the way that Trades arrive. Dividends are expected to have adjusted payment
amounts that are inline with adjusted trades.
PerformanceTracker maintains state of all the unpaid dividends in the position
objects held in PerformancePeriod. Dividend objects contain all the relevant
dates (declared, ex, payment) as well as net and gross amounts. Dividends are
removed from the list as they are paid. Cash flow is not incremented until the
payment day. This creates the possibility of a dividend being owed but not
paid or realized before the end of a test. For example, a dividend with an
ex_date of today may have a pay date 2 weeks in the future. Right now the
algorithm does not receive any credit for unpaid dividends.
Tests cover buying/selling around the ex_date and payment_date, and checking
that the performance calculated is as expected.
Eddie Hebert