fit_v1¶

The module initializes a fit process with a minimizer, provided by minimizer-v1, minimizer-scan or others.

The fit result is saved to the env.future[‘fitresult’] as a dictionary.

Positional arguments

minimizer – define name of the minimizer to use

Options

-s, --set – set best fit parameters

-p, --push – set (push) best fit parameters

-l, --label – define the label to use to write results

--profile-errors – calculate errors based on statistics profile

--scan – calculate profiles for parameters

--covariance, --cov – estimate covariance matrix

--simulate – do nothing

--ndf – read NDF for given chi2 from env

-v, --verbose – print fit result to stdout

Examples

Perform a fit using a minimizer ‘min’:

./gna \
    -- gaussianpeak --name peak_MC --nbins 50 \
    -- gaussianpeak --name peak_f  --nbins 50 \
    -- ns --name peak_MC --print \
        --set E0             values=2    fixed \
        --set Width          values=0.5  fixed \
        --set Mu             values=2000 fixed \
        --set BackgroundRate values=1000 fixed \
    -- ns --name peak_f --print \
        --set E0             values=2.5  relsigma=0.2 \
        --set Width          values=0.3  relsigma=0.2 \
        --set Mu             values=1500 relsigma=0.25 \
        --set BackgroundRate values=1100 relsigma=0.25 \
    -- dataset-v1  peak --theory-data peak_f.spectrum peak_MC.spectrum \
    -- analysis-v1 analysis --datasets peak \
    -- stats stats --chi2 analysis \
    -- pargroup minpars peak_f -vv \
    -- minimizer-v1 min stats minpars -vv \
    -- fit-v1 min

By default the parameters are set to initial after the minimization is done. It is possible to set the best fit parameters with option -s or with option -p. The latter option pushed the current values to the stack so they can be recovered in the future.

The result of the fit may be saved with save_pickle or save_yaml module.