uniform_sample
- sherpa.astro.ui.uniform_sample(num=1, factor=4, id: IdType | None = None, otherids: Sequence[IdType] = (), numcores=None)
Sample the fit statistic by taking the parameter values from an uniform distribution.
For each iteration (sample), change the thawed parameters by drawing values from a uniform distribution, and calculate the fit statistic.
- Parameters:
num (int, optional) – The number of samples to use (default is 1).
factor (number, optional) – Multiplier to expand the scale parameter (default is 4).
id (int, str, or None, optional) – The data set that provides the data. If not given then all data sets with an associated model are used simultaneously.
otherids (sequence of int or str, optional) – Other data sets to use in the calculation.
numcores (optional) – The number of CPU cores to use. The default is to use all the cores on the machine.
- Returns:
A NumPy array table with the first column representing the statistic and later columns the parameters used.
- Return type:
samples
See also
fit
Fit a model to one or more data sets.
normal_sample
Sample from a normal distribution.
set_model
Set the source model expression for a data set.
set_stat
Set the statistical method.
t_sample
Sample from the Student’s t-distribution.
Examples
The model fit to the default data set has three free parameters. The median value of the statistic calculated by
uniform_sample
is returned:>>> ans = uniform_sample(num=10000) >>> ans.shape (1000, 4) >>> np.median(ans[:,0]) 284.66534775948134