# ¶

iminuit is a Jupyter-friendly Python interface for the Minuit2 C++ library maintained by CERN’s ROOT team.

It can be used as a general robust function minimisation method, but is most commonly used for likelihood fits of models to data, and to get model parameter error estimates from likelihood profile analysis.

• Supported CPython versions: 3.6+
• Supported PyPy versions: 3.6
• Supported platforms: Linux, OSX and Windows.

## In a nutshell¶

from iminuit import Minuit

def fcn(x, y, z):
return (x - 2) ** 2 + (y - 3) ** 2 + (z - 4) ** 2

fcn.errordef = Minuit.LEAST_SQUARES

m = Minuit(fcn, x=0, y=0, z=0)


All interface changes are documented in the changelog with recommendations how to upgrade. To keep existing scripts running, pin your major iminuit version to <2, i.e. pip install 'iminuit<2' installs the 1.x series.