formulate 1.0.1

Easy conversions between different styles of expressions

formulate

Formulate

Easy conversions between different styles of expressions. Formulate currently supports converting between ROOT and numexpr style expressions.

Installation

Install formulate like any other Python package, ideally inside a virtual environment:

pip install formulate

or using conda:

conda install -c conda-forge formulate

(-c conda-forge is only needed if you don't have the conda-forge channel already configured)

Roadmap and releases

For the roadmap, planned features, breaking changes and versioning please see the roadmap.

Usage

API

The most basic usage involves calling from_$BACKEND and then to_$BACKEND, for example when starting with a ROOT style expression:

>>> import formulate
>>> momentum = formulate.from_root("TMath::Sqrt(X_PX**2 + X_PY**2 + X_PZ**2)")
>>> momentum
Call(function='sqrt', arguments=[BinaryOperator(operator='add', left=BinaryOperator(operator='add', left=BinaryOperator(operator='pow', left=Symbol(name='X_PX'), right=Literal(value=2)), right=BinaryOperator(operator='pow', left=Symbol(name='X_PY'), right=Literal(value=2))), right=BinaryOperator(operator='pow', left=Symbol(name='X_PZ'), right=Literal(value=2)))])
>>> momentum.to_numexpr()
'sqrt((((X_PX ** 2) + (X_PY ** 2)) + (X_PZ ** 2)))'
>>> momentum.to_root()
'TMath::Sqrt((((X_PX ** 2) + (X_PY ** 2)) + (X_PZ ** 2)))'

Similarly, when starting with a numexpr style expression:

>>> my_selection = formulate.from_numexpr("(X_PT > 5) & ((Mu_NHits > 3) | (Mu_PT > 10))")
>>> my_selection.to_root()
'((X_PT > 5) && ((Mu_NHits > 3) || (Mu_PT > 10)))'
>>> my_selection.to_numexpr()
'((X_PT > 5) & ((Mu_NHits > 3) | (Mu_PT > 10)))'

CLI

The package also provides a command-line interface for converting expressions between different styles. To use it, simply run the formulate command followed by the input expression and the desired output.

$ formulate --from-root '(A && B) || TMath::Sqrt(A)' --to-numexpr
((A & B) | sqrt(A))

$ formulate --from-numexpr '(A & B) | sqrt(A)' --to-root
((A && B) || TMath::Sqrt(A))

$ formulate --from-root '(A && B) || TMath::Sqrt(1.23) * e_num**1.2 + 5*pi' --variables
A
B

$ formulate --from-root '(A && B) || TMath::Sqrt(1.23) * e_num**1.2 + 5*pi' --named-constants
exp1
pi

$ formulate --from-root '(A && B) || TMath::Sqrt(1.23) * e_num**1.2 + 5*pi' --unnamed-constants
1.23
1.2
5