dataspace1d

sherpa.astro.ui.dataspace1d(start, stop, step=1, numbins=None, id=None, bkg_id=None, dstype=<class 'sherpa.data.Data1DInt'>)

Create the independent axis for a 1D data set.

Create an “empty” one-dimensional data set by defining the grid on which the points are defined (the independent axis). The values are set to 0.

Parameters:
  • start (number) – The minimum value of the axis.
  • stop (number) – The maximum value of the axis.
  • step (number, optional) – The separation between each grid point. This is not used if numbins is set.
  • numbins (int, optional) – The number of grid points. This over-rides the step setting.
  • id (int or str, optional) – The identifier for the data set to use. If not given then the default identifier is used, as returned by get_default_id.
  • bkg_id (int or str, optional) – If set, the grid is for the background component of the data set.
  • dstype (data class to use, optional) – What type of data is to be used. Supported values include Data1DInt (the default), Data1D, and DataPHA.

See also

dataspace2d()
Create the independent axis for a 2D data set.
get_dep()
Return the dependent axis of a data set.
get_indep()
Return the independent axes of a data set.
set_dep()
Set the dependent axis of a data set.

Notes

The meaning of the stop parameter depends on whether it is a binned or unbinned data set (as set by the dstype parameter).

Examples

Create a binned data set, starting at 1 and with a bin-width of 1.

>>> dataspace1d(1, 5, 1)
>>> print(get_indep())
(array([ 1.,  2.,  3.,  4.]), array([ 2.,  3.,  4.,  5.]))

This time for an un-binned data set:

>>> dataspace1d(1, 5, 1, dstype=Data1D)
>>> print(get_indep())
(array([ 1.,  2.,  3.,  4.,  5.]),)

Specify the number of bins rather than the grid spacing:

>>> dataspace1d(1, 5, numbins=5, id=2)
>>> (xlo, xhi) = get_indep(2)
>>> xlo
array([ 1. ,  1.8,  2.6,  3.4,  4.2])
>>> xhi
array([ 1.8,  2.6,  3.4,  4.2,  5. ])

>>> dataspace1d(1, 5, numbins=5, id=3, dstype=Data1D)
>>> (x, ) = get_indep(3)
>>> x
array([ 1.,  2.,  3.,  4.,  5.])

Create a grid for a PHA data set called ‘jet’, and for its background component:

>>> dataspace1d(0.01, 11, 0.01, id='jet', dstype=DataPHA)
>>> dataspace1d(0.01, 11, 0.01, id='jet', bkg_id=1,
                dstype=DataPHA)