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Gabriele Gilardi 2020-06-28 11:22:24 +09:00
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.gitignore vendored
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@ -150,4 +150,6 @@ Code_MatLab/
# Docs directory
Docs/
# Data directory
data/

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@ -649,7 +649,7 @@ class Filter:
plt.ylabel('$h$ [db]')
legend = ['Filter', '-3dB']
plt.legend(legend)
plt.title('Frequency Response', fontweight="bold")
plt.title('Frequency Response')
# Plot and format lag/group delay
plt.subplot(1, 2, 2)
@ -658,7 +658,8 @@ class Filter:
plt.xlim(np.amin(wf), np.amax(wf))
plt.xlabel(r'$\omega$ [rad/sample]')
plt.ylabel('$gd$ [samples]')
plt.title('Lag / Group Delay', fontweight="bold")
plt.title('Lag / Group Delay')
# Show plots
plt.suptitle('Example "Response"')
plt.show()

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@ -3,19 +3,112 @@ Signal Filtering and Generation of Synthetic Time-Series.
Copyright (c) 2020 Gabriele Gilardi
References
----------
- John F. Ehlers, "Cycle Analytics for Traders: Advanced Technical Trading
Concepts", @ http://www.mesasoftware.com/ehlers_books.htm.
- D. Prichard and J. Theiler, "Generating surrogate data for time series with
several simultaneously measured variables",
@ https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.73.951.
- H. Vinod and J. Lopez-de-Lacalle, "Maximum entropy bootstrap for time series:
the meboot R package, @ https://www.jstatsoft.org/article/view/v029i05.
Characteristics
---------------
- The code has been written and tested in Python 3.7.7.
- Implementation of several digital signal filters and functions for the
generation of synthetic (surrogate) time-series.
- Filter list (file <filters.py>):
Generic Generic filter
SMA Simple moving average
EMA Exponential moving average
WMA Weighted moving average
MSMA Modified simple moving average
MLSQ Modified least-squares quadratic
ButterOrig Butterworth original filter
ButterMod Butterworth modified filter
SuperSmooth Supersmoother filter
GaussLow Gauss low pass filter
GaussHigh Gauss high pass filter
BandPass Band-pass filter
BandStop Band-stop filter
ZEMA1 Zero-lag EMA (type 1)
ZEMA2 Zero-lag EMA (type 2)
InstTrend Instantaneous trendline
SincFilter Sinc function filter
Decycler De-cycler filter
DecyclerOsc De-cycle oscillator
ABG Alpha-beta-gamma filter
Kalman One-dimensional steady-state Kalman filter
- Synthetic time-series (file <synthetic.py>):
synthetic_wave Generates multi-sine wave given periods,
amplitudes, and phases.
synthetic_sampling Generates surrogates using randomized-sampling
(bootstrap) with or without replacement.
synthetic_FFT Generates surrogates using the phase-randomized
Fourier transform algorithm.
synthetic_MEboot Generates surrogates using the maximum entropy
bootstrap algorithm.
- File <filters.py> includes also functions to plot the filter signal,
frequency response, and group delay.
- File <synthetic.py> includes also functions to differentiate, integrate,
normalize, and scale the discrete time-series.
- Usage: python test.py <example>.
Parameters
----------
example
Name of the example to run (Filters, Kalman, FFT_boot, ME_boot, Response).
data_file
File with the dataset (csv format). The extension is added automatically.
X
Dataset to filter/time-series (input). It must be a 1D array, i.e. of shape
(:, ) or (:, 1) or (1, :).
b
Transfer response coefficients (numerator).
a
Transfer response coefficients (denominator).
Y
Filtered dataset (output).
X_synt
Surrogate/synthetic generated time-series (output)
n_reps
Number of surrogates/synthetic time-series to generate.
Examples
--------
There are five examples (all of them use the dataset in *spx.csv*). The
results are shown in file <Results_Examples.pdf>.
- Filter: example showing filtering using an EMA, a Butterworth modified
filter, and a type 2 Zero-lag EMA.
- Kalman: example showing filtering using the three types of Kalman filter,
alpha, alpha-beta, and alpha-beta-gamma.
- FFT_boot: example showing the generation of surrogates time-series using
the Fourier-transform algorithm and the discrete differences.
- ME_boot: example showing the generation of surrogates time-series using the
using maximum entropy bootstrap algorithm and the discrete differences.
- Response: example showing the frequency response and lag/group delay for a
band-pass filter.
"""
import sys
import warnings
import numpy as np
import matplotlib.pyplot as plt
import filters as flt
import synthetic as syn
# Added to avoid message warning "The group delay is singular at frequencies
# [....], setting to 0" when plotting the lag for SMA filters.
# np.seterr(all='ignore')
# [....], setting to 0" when plotting the lag for SMA filters.
warnings.filterwarnings('ignore')
np.random.seed(1294404794)
@ -29,7 +122,7 @@ example = sys.argv[1]
data_file = 'spx'
data = np.loadtxt(data_file + '.csv', delimiter=',')
# Example with a few filters
# Example with an EMA, a Butterworth modified filter, and a type 2 Zero-lag EMA
if (example == 'Filters'):
spx = flt.Filter(data)
ema = spx.EMA(N=10)
@ -49,38 +142,53 @@ elif (example == 'Kalman'):
names = ['SPX', 'a-type', 'ab-type', 'abg-type']
flt.plot_signals(signals, names=names, start=0, end=200)
# Example of filter frequency and lag
# Example of surrogates time-series using the Fourier-transform algorithm
elif (example == 'FFT_boot'):
n_reps = 4
n_samples = len(data)
# Generated the surrogates using the 1st discrete differences (in percent)
dX = syn.value2diff(data, percent=True)
dX_synt = syn.synthetic_FFT(dX, n_reps=n_reps) # (n_reps, n_samples)
# Rebuild the actual surrogate time-series
signals = [data]
names = ['SPX']
for i in range(n_reps):
X_synt = syn.diff2value(dX_synt[i, :], data[0], percent=True)
signals.append(X_synt)
names.append('Synth. #' + str(i+1))
# Plot all
flt.plot_signals(signals, names=names, start=0, end=200)
# Example of surrogates time-series using the maximum entropy bootstrap algorithm
elif (example == 'ME_boot'):
n_reps = 4
n_samples = len(data)
# Generated the surrogates using the 1st discrete differences (in value)
dX = syn.value2diff(data, percent=False)
dX_synt = syn.synthetic_MEboot(dX, n_reps=n_reps, alpha=0.1, bounds=False,
scale=False) # (n_reps, n_samples)
# Rebuild the actual surrogate time-series
signals = [data]
names = ['SPX']
for i in range(n_reps):
X_synt = syn.diff2value(dX_synt[i, :], data[0], percent=False)
signals.append(X_synt)
names.append('Synth. #' + str(i+1))
# Plot all
flt.plot_signals(signals, names=names, start=0, end=499)
# Example of frequency response and lag/group delay for a band-pass filter
elif (example == 'Response'):
spx = flt.Filter(data)
band = spx.BandPass(P=10, delta=0.3)
spx.plot_response()
# Example of surrogates time-series using the Fourier-transform algorithm
elif (example == 'FFT_boot'):
pass
# Example of surrogates time-series using maximum entropy bootstrap algorithm
elif (example == 'ME_boot'):
pass
else:
print("Example not found")
sys.exit(1)
# dX = syn.value2diff(data, percent=True)
# # X = syn.diff2value(dX, data[0], percent=True)
# signals = [data, X]
# flt.plot_signals(signals, start=0, end=200)
# dX = syn.value2diff(data, percent=False)
# dX_synt = syn.synthetic_sampling(dX, n_reps=1, replace=True)
# dX_synt = syn.synthetic_FFT(dX, n_reps=2)
# dX_synt = syn.synthetic_MEboot(dX, n_reps=4, alpha=0.1, bounds=False, scale=False)
# for i in range(dX_synt.shape[0]):
# # aa = dX_synt[:, i]
# aa = syn.diff2value(dX_synt[i, :], data[0], percent=False)
# plt.plot(aa)
# plt.xlim(0, 200)
# plt.plot(data)
# plt.show()

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@ -45,9 +45,9 @@
## Main Parameters
`example` Name of the example to run.
`example` Name of the example to run (Filters, Kalman, FFT_boot, ME_boot, Response).
`data_file` File name with the dataset (csv format). The extension is added automatically.
`data_file` File with the dataset (csv format). The extension is added automatically.
`X` Dataset to filter/time-series (input). It must be a 1D array, i.e. of shape `(:, )` or `(:, 1)` or `(1, :)`.
@ -57,10 +57,20 @@
`Y` Filtered dataset (output).
`X_synt` Synthetic time-series (output)
`X_synt` Surrogate/synthetic generated time-series (output)
`n_reps` Number of surrogates/synthetic time-series to generate.
## Examples
There are five examples: **Filters**, **Kalman**, **Response**, **FFT_boot**, **ME_boot**. For all, the dataset in *spx.csv* is used.
There are five examples (all of them use the dataset in *spx.csv*). The results are shown [here](Results_Examples.pdf).
- **Filter** Example showing filtering using an EMA, a Butterworth modified filter, and a type 2 Zero-lag EMA.
- **Kalman** Example showing filtering using the three types of Kalman filter, alpha, alpha-beta, and alpha-beta-gamma.
- **FFT_boot** Example showing the generation of surrogates time-series using the Fourier-transform algorithm and the discrete differences.
- **ME_boot** Example showing the generation of surrogates time-series using the using maximum entropy bootstrap algorithm and the discrete differences.
- **Response** Example showing the frequency response and lag/group delay for a band-pass filter.

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