vectorbt is a backtesting library on steroids - it operates entirely on pandas and NumPy, and is accelerated by Numba to analyze trading strategies at speed and scale 🔥
It follows a unique approach to backtesting that builds upon vectorized matrix calculations and fast iterative processing with Numba. It also integrates plotly.py and ipywidgets to display complex charts and dashboards akin to Tableau right in the Jupyter notebook. Due to its high processing performance, vectorbt is able to process data on the fly and thus enable the user to interact with data-hungry widgets without significant delays.
With vectorbt you can
- Analyze and engineer features for any time series data
- Supercharge pandas and your favorite tools to run much faster
- Test thousands of strategies, configurations, assets, and time ranges in one go
- Test machine learning models
- Build interactive charts/dashboards without leaving Jupyter
Here a snippet for testing 4851 window combinations of a dual SMA crossover strategy on the whole Bitcoin history in under 5 seconds (Note: compiling for the first time may take a while):
import vectorbt as vbt
import numpy as np
import yfinance as yf
# Fetch daily price of Bitcoin
price = yf.Ticker("BTC-USD").history(period="max")['Close']
# Compute moving averages for all combinations of fast and slow windows
fast_ma, slow_ma = vbt.MA.from_combs(
price, np.arange(2, 101), 2,
names=['fast', 'slow'],
hide_params=['ewm']
)
# Generate crossover signals for each combination
entries = fast_ma.ma_above(slow_ma, crossed=True)
exits = fast_ma.ma_below(slow_ma, crossed=True)
# Model performance
portfolio = vbt.Portfolio.from_signals(price, entries, exits, fees=0.001, freq='1D')
# Get total return, reshape to symmetric matrix, and plot the whole thing
portfolio.total_return.vbt.heatmap(
x_level='fast_window', y_level='slow_window', symmetric=True,
trace_kwargs=dict(colorbar=dict(title='Total return', tickformat='%'))
)
Digging into each individual strategy instance is as simple as indexing with pandas:
>>> print(portfolio[(13, 21)].stats)
Start 2014-09-17 00:00:00
End 2020-07-15 00:00:00
Duration 2129 days 00:00:00
Holding Duration [%] 56.4584
Total Profit 9626.46
Total Return [%] 9626.46
Buy & Hold Return [%] 1909.76
Max. Drawdown [%] 47.8405
Avg. Drawdown [%] 8.72147
Max. Drawdown Duration 510 days 00:00:00
Avg. Drawdown Duration 37 days 07:06:40
Num. Trades 54
Win Rate [%] 51.8519
Best Trade [%] 279.692
Worst Trade [%] -23.4948
Avg. Trade [%] 13.459
Max. Trade Duration 100 days 00:00:00
Avg. Trade Duration 22 days 06:13:20
Expectancy 178.268
SQN 1.9641
Sharpe Ratio 1.77836
Sortino Ratio 2.81075
Calmar Ratio 2.49139
Name: (13, 21), dtype: object
While there are many other great backtesting packages for Python, vectorbt is more of a data science tool: it excels at processing performance and offers interactive tools to explore complex phenomena in trading. With it you can traverse a huge number of strategy configurations, time periods and instruments in little time, to explore where your strategy performs best and to uncover hidden patterns in data.
Take a simple Dual Moving Average Crossover strategy for example. By calculating the performance of each reasonable window combination and plotting the whole thing as a heatmap (as we do above), you can easily identify how performance depends on window size. If you additionally compute the same heatmap over multiple time periods, you will spot how performance varies with downtrends and uptrends. Finally, by running the same pipeline on other strategies such as holding and trading randomly, you can compare them and decide whether your strategy is worth executing. With vectorbt, this analysis can be done in minutes, and will effectively save you nights of getting the same insights using other libraries.
vectorbt combines pandas, NumPy and Numba sauce to obtain orders-of-magnitude speedup over other libraries. It natively works on pandas objects, while performing all computations using NumPy and Numba under the hood. This way, it is often much faster than pandas alone:
>>> import numpy as np
>>> import pandas as pd
>>> import vectorbt as vbt
>>> big_ts = pd.DataFrame(np.random.uniform(size=(1000, 1000)))
# pandas
>>> %timeit big_ts.expanding().max()
48.4 ms ± 557 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)
# vectorbt
>>> %timeit big_ts.vbt.expanding_max()
8.82 ms ± 121 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
In contrast to most other similar backtesting libraries where backtesting is limited to simple arrays (think of an array for price, an array for signals, etc.), vectorbt is optimized for working with 2-dimensional data: it treats index of a DataFrame as time axis and columns as distinct features that should be backtested, and performs calculations on the entire matrix at once. This way, user can construct huge matrices with thousands of columns and calculate the performance for each one with a single matrix operation, without any Pythonic loops.
To make the library easier to use, vectorbt introduces a namespace (accessor) to pandas objects (see extending pandas). This way, user can easily switch between native pandas functionality and highly-efficient vectorbt methods. Moreover, each vectorbt method is flexible and can work on both Series and DataFrames.
- Extends pandas using a custom
vbtaccessor -> Compatible with any library - For high performance, most operations are done strictly using NumPy and Numba -> Much faster than comparable operations in pandas
# pandas
>>> %timeit big_ts + 1
242 ms ± 3.58 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
# vectorbt
>>> %timeit big_ts.vbt + 1
3.32 ms ± 19.7 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
- Helper functions for combining, transforming, and indexing NumPy and pandas objects
- NumPy-like broadcasting for pandas, among other features
# pandas
>>> pd.Series([1, 2, 3]) + pd.DataFrame([[1, 2, 3]])
0 1 2
0 2 4 6
# vectorbt
>>> pd.Series([1, 2, 3]).vbt + pd.DataFrame([[1, 2, 3]])
0 1 2
0 2 3 4
1 3 4 5
2 4 5 6
- Compiled versions of common pandas functions, such as rolling, groupby, and resample
# pandas
>>> %timeit big_ts.rolling(2).apply(np.mean, raw=True)
7.32 s ± 431 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
# vectorbt
>>> mean_nb = njit(lambda col, i, x: np.mean(x))
>>> %timeit big_ts.vbt.rolling_apply(2, mean_nb)
86.2 ms ± 7.97 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
- Drawdown analysis
>>> pd.Series([2, 1, 3, 2]).vbt.drawdowns.plot()
- Functions for working with signals
- Entry, exit and random signal generation, ranking and distance functions
- Stop loss, trailing stop and take profit signal generation
>>> pd.Series([False, True, True, True]).vbt.signals.first()
0 False
1 True
2 False
3 False
dtype: bool
- Functions for working with returns
- Compiled versions of metrics found in empyrical
>>> pd.Series([0.01, -0.01, 0.01]).vbt.returns(freq='1D').sharpe_ratio()
5.515130702591433
- Class for modeling portfolio performance
- Accepts signals, orders, and custom order function
- Provides metrics and tools for analyzing returns, orders, trades and positions
>>> price = pd.Series([1, 2, 3, 2, 1])
>>> entries = pd.Series([True, False, True, False, False])
>>> exits = pd.Series([False, True, False, True, False])
>>> portfolio = vbt.Portfolio.from_signals(price, entries, exits, freq='1D')
>>> portfolio.trades.plot()
- Technical indicators with full Numba support
- Moving average and STD, Bollinger Bands, RSI, Stochastic Oscillator, MACD, and more.
- Each offering methods for generating signals and plotting
- Each allowing arbitrary parameter combinations, from arrays to Cartesian products
- Indicator factory for building complex technical indicators in a simple way
>>> vbt.MA.from_params(pd.Series([1, 2, 3]), window=[2, 3], ewm=[False, True]).ma
ma_window 2 3
ma_ewm False True
0 NaN NaN
1 1.5 NaN
2 2.5 2.428571
- Interactive Plotly-based widgets to visualize backtest results
- Bar, Scatter, Histogram, Box and Heatmap
- Each provides a method for efficiently updating data
- Full integration with ipywidgets for displaying interactive dashboards in Jupyter
>>> a = np.random.normal(0, 4, size=10000)
>>> pd.Series(a).vbt.box(horizontal=True, trace_kwargs=dict(boxmean='sd'))
pip install vectorbt
See Jupyter Notebook and JupyterLab Support for Plotly figures.
- Who beats Bitcoin: Dual moving average crossover, trading randomly or holding?
- How stop-loss and trailing stop orders perform on crypto?
Note: you will need to run the notebook to play with widgets.