ParamTools

Define, update, and validate your model's parameters.

Install using pip:

pip install paramtools

Install using conda:

conda install -c conda-forge paramtools

Usage

Subclass paramtools.Parameters and define your model's parameters:

importparamtoolsclassParams(paramtools.Parameters):
defaults= {
"schema": {
"labels": {
"date": {
"type": "date",
"validators": {
"range": {
"min": "2020-01-01",
"max": "2021-01-01",
"step": {"months": 1}
}
}
}
},
},
"a": {
"title": "A",
"type": "int",
"value": [
{"date": "2020-01-01", "value": 2},
{"date": "2020-10-01", "value": 8},
],
"validators": {
"range" : {
"min": 0, "max": "b"
}
}
},
"b": {
"title": "B",
"type": "float",
"value": [{"date": "2020-01-01", "value": 10.5}]
}
}

Access parameter values

Access values using .sel:

params=Params()
params.sel["a"]

Values([
{'date': datetime.date(2020, 1, 1), 'value': 2},
{'date': datetime.date(2020, 10, 1), 'value': 8},
])

Look up parameter values using a pandas-like api:

fromdatetimeimportdateresult=params.sel["a"]["date"] ==date(2020, 1, 1)
result

QueryResult([
{'date': datetime.date(2020, 1, 1), 'value': 2}
])

result.isel[0]["value"]

2

Adjust and validate parameter values

Add a new value:

params.adjust({"a": [{"date": "2020-11-01", "value": 22}]})
params.sel["a"]

Values([
{'date': datetime.date(2020, 1, 1), 'value': 2},
{'date': datetime.date(2020, 10, 1), 'value': 8},
{'date': datetime.date(2020, 11, 1), 'value': 22},
])

Update an existing value:

params.adjust({"a": [{"date": "2020-01-01", "value": 3}]})
params.sel["a"]

Values([
{'date': datetime.date(2020, 1, 1), 'value': 3},
{'date': datetime.date(2020, 10, 1), 'value': 8},
{'date': datetime.date(2020, 11, 1), 'value': 22},
])

Update all values:

params.adjust({"a": 7})
params.sel["a"]

Values([
{'date': datetime.date(2020, 1, 1), 'value': 7},
{'date': datetime.date(2020, 10, 1), 'value': 7},
{'date': datetime.date(2020, 11, 1), 'value': 7},
])

Errors on values that are out of range:

params.adjust({"a": -1})

---------------------------------------------------------------------------
ValidationError Traceback (most recent call last)
<ipython-input-8-f8f1b7f6cd9a> in <module>
----> 1 params.adjust({"a": -1})
~/Paramtools/paramtools/parameters.py in adjust(self, params_or_path, ignore_warnings, raise_errors, extend_adj, clobber)
253 least one existing value item's corresponding label values.
254 """
--> 255 return self._adjust(
256 params_or_path,
257 ignore_warnings=ignore_warnings,
~/Paramtools/paramtools/parameters.py in _adjust(self, params_or_path, ignore_warnings, raise_errors, extend_adj, is_deserialized, clobber)
371 not ignore_warnings and has_warnings
372 ):
--> 373 raise self.validation_error
374
375 # Update attrs for params that were adjusted.
ValidationError: {
"errors": {
"a": [
"a -1 < min 0 "
]
}
}

params=Params()
params.adjust({"a": [{"date": "2020-01-01", "value": 11}]})

---------------------------------------------------------------------------
ValidationError Traceback (most recent call last)
<ipython-input-9-cc8a21f044d8> in <module>
1 params = Params()
2
----> 3 params.adjust({"a": [{"date": "2020-01-01", "value": 11}]})
~/Paramtools/paramtools/parameters.py in adjust(self, params_or_path, ignore_warnings, raise_errors, extend_adj, clobber)
253 least one existing value item's corresponding label values.
254 """
--> 255 return self._adjust(
256 params_or_path,
257 ignore_warnings=ignore_warnings,
~/Paramtools/paramtools/parameters.py in _adjust(self, params_or_path, ignore_warnings, raise_errors, extend_adj, is_deserialized, clobber)
371 not ignore_warnings and has_warnings
372 ):
--> 373 raise self.validation_error
374
375 # Update attrs for params that were adjusted.
ValidationError: {
"errors": {
"a": [
"a[date=2020-01-01] 11 > max 10.5 b[date=2020-01-01]"
]
}
}

Errors on invalid values:

params=Params()
params.adjust({"b": "abc"})

---------------------------------------------------------------------------
ValidationError Traceback (most recent call last)
<ipython-input-10-8373a2715e38> in <module>
1 params = Params()
2
----> 3 params.adjust({"b": "abc"})
~/Paramtools/paramtools/parameters.py in adjust(self, params_or_path, ignore_warnings, raise_errors, extend_adj, clobber)
253 least one existing value item's corresponding label values.
254 """
--> 255 return self._adjust(
256 params_or_path,
257 ignore_warnings=ignore_warnings,
~/Paramtools/paramtools/parameters.py in _adjust(self, params_or_path, ignore_warnings, raise_errors, extend_adj, is_deserialized, clobber)
371 not ignore_warnings and has_warnings
372 ):
--> 373 raise self.validation_error
374
375 # Update attrs for params that were adjusted.
ValidationError: {
"errors": {
"b": [
"Not a valid number: abc."
]
}
}

Extend parameter values using label definitions

Extend values using label_to_extend:

params=Params(label_to_extend="date")

params.sel["a"]

Values([
{'date': datetime.date(2020, 1, 1), 'value': 2},
{'date': datetime.date(2020, 2, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 3, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 4, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 5, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 6, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 7, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 8, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 9, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 10, 1), 'value': 8},
{'date': datetime.date(2020, 11, 1), 'value': 8, '_auto': True},
{'date': datetime.date(2020, 12, 1), 'value': 8, '_auto': True},
{'date': datetime.date(2021, 1, 1), 'value': 8, '_auto': True},
])

Updates to values are carried through to future dates:

params.adjust({"a": [{"date": "2020-4-01", "value": 9}]})
params.sel["a"]

Values([
{'date': datetime.date(2020, 1, 1), 'value': 2},
{'date': datetime.date(2020, 2, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 3, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 4, 1), 'value': 9},
{'date': datetime.date(2020, 5, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 6, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 7, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 8, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 9, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 10, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 11, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 12, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2021, 1, 1), 'value': 9, '_auto': True},
])

Use clobber to only update values that were set automatically:

params=Params(label_to_extend="date")
params.adjust(
{"a": [{"date": "2020-4-01", "value": 9}]},
clobber=False,
)
# Sort parameter values by date for nicer outputparams.sort_values()
params.sel["a"]

Values([
{'date': datetime.date(2020, 1, 1), 'value': 2},
{'date': datetime.date(2020, 2, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 3, 1), 'value': 2, '_auto': True},
{'date': datetime.date(2020, 4, 1), 'value': 9},
{'date': datetime.date(2020, 5, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 6, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 7, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 8, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 9, 1), 'value': 9, '_auto': True},
{'date': datetime.date(2020, 10, 1), 'value': 8},
{'date': datetime.date(2020, 11, 1), 'value': 8, '_auto': True},
{'date': datetime.date(2020, 12, 1), 'value': 8, '_auto': True},
{'date': datetime.date(2021, 1, 1), 'value': 8, '_auto': True},
])

NumPy integration

Access values as NumPy arrays with array_first:

params=Params(label_to_extend="date", array_first=True)
params.a

array([2, 2, 2, 2, 2, 2, 2, 2, 2, 8, 8, 8, 8])

params.a*params.b

array([21., 21., 21., 21., 21., 21., 21., 21., 21., 84., 84., 84., 84.])

Only get the values that you want:

arr=params.to_array("a", date=["2020-01-01", "2020-11-01"])
arr

array([2, 8])

Go back to a list of dictionaries:

params.from_array("a", arr, date=["2020-01-01", "2020-11-01"])

[{'date': datetime.date(2020, 1, 1), 'value': 2},
{'date': datetime.date(2020, 11, 1), 'value': 8}]

Documentation

Full documentation available at paramtools.dev.

Contributing

Contributions are welcome! Checkout CONTRIBUTING.md to get started.

Credits

ParamTools is built on top of the excellent marshmallow JSON schema and validation framework. I encourage everyone to check out their repo and documentation. ParamTools was modeled off of Tax-Calculator's parameter processing and validation engine due to its maturity and sophisticated capabilities.