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python-monitors is a pure Python package to monitor formal specifications over temporal sequences. It supports several specification languages such as regular expressions and variants of temporal logic. The usage is fairly easy thanks to Python and allows fast prototyping of applications that monitor temporal sequences using these specifications.

WARNING: This repository is depreciated in favor of the projectReelay but will remain as a pure Python solution albeit limited in functionatity and speed. Reelay implements the same runtime monitors and more in C++, which are accessible from Python via bindings.

The latest release of the package can be installed viapip such that

pip install python-monitors

This command will also install dependenciespython-intervals andantlr4-python3-runtime. Alternatively, you can install directly from this repository by running the command

pip install git+https://github.com/doganulus/python-monitors.git

First generate a monitor from past Metric Temporal Logic (MTL) formula:

from monitors import mtl my_mtl_monitor = mtl.monitor("always(q -> once[2,4](p))")

Then process a data sequence (over propositions) by updating the monitor and collecting the output at each step:

data = dict(p = [False, True,  False, False, False, False, False, True,  False, False, False, False, False, False, False], q = [False, False, False, False, False, True,  False, False, False, False, False, False, False, False, True ]) for p, q in zip(data['p'], data['q']): output = my_mtl_monitor.update(p = p, q = q) print(my_mtl_monitor.time, output, my_mtl_monitor.states)

Any Boolean-valued Python function can be used as a predicate in MTL formulas. They are passed to monitor construction via a dictionary as follows:

def my_predicate(x):    return x < 5# Named parameters should share the same strings in the expression my_mtl_monitor = mtl.monitor("always[0,5](p(x))", p=my_predicate) for n in [9, 13, 4, 1, 2, 3,1,1,1,2]:    output = my_mtl_monitor.update(x = n)    print(my_mtl_monitor.time, my_predicate(n), output, my_mtl_monitor.states)

Regular expressions over propositions and predicates are available in a similar fashion:

from monitors import regexp def pred1(x):    return x < 5 def pred2(x):    return x > 12 # Named parameters should share the same strings in the expression my_reg_monitor = regexp.monitor("True*; p1(x); p2(x)+; p1(x)+", p1=pred1, p2=pred2) for n in [1, 1, 1, 1, 13, 13, 14, 1, 1, 2]:    output = my_reg_monitor.update(x = n)    print(output, my_reg_monitor.states)

For MTL monitoring algorithm, please citeOnline Monitoring of Metric Temporal Logic using Sequential Networks. For RE monitoring algorithm, please citeSequential Circuits from Regular Expressions Revisited.