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Last modified: December 2010

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AHELP for CIAO 4.3 Sherpa v1


Context: filtering


Apply an include filter to all 1D datasets


notice( [lo,hi] )
notice( expr )


The notice command specifies the portion of 1D data to be included in the analysis. The filter is applied to all available dataset ids; to operate on specific ids, use the notice_id command ("ahelp notice_id").

  • lo: lower bound of the filter; default=None
  • hi: upper bound of the filter; default=None
  • expr: a filter expression to notice an intersection of filters, e.g. "0.1:5, 6:7". Range filtering allows ":#" and "#:", which includes an open-ended range of data up to or beginning at the given value (#), respectively.

The units for the limits are determined by the "units" field of the data structure: channels, energy (keV), or wavelength (angstrom). The value can be obtained by using the get_analysis command ("ahelp get_analysis").

If no limits are supplied, all data points in all datasets are included. Noticing the entire set is a method of clearing any filters that have been applied. It is also possible to specify just a lower limit or just an upper limit; the unspecified value will remain at the data minimum or maximum.

If the data is binned and the endpoint of the interval falls within a bin, the entire bin is included in the filter.

Two-dimensional Data Filtering

To apply an include filter to 2D data, use the notice2d command ("ahelp notice2d") or the notice2d_id command ("ahelp notice2d_id").

Example 1

sherpa> notice()

When the command is called without any arguments, all data points in all sets are included.

Example 2

sherpa> notice(1.0, 6.0)

Apply a filter to notice the range 1.0-6.0 keV in all datasets.

Example 3

sherpa> notice(10,)
sherpa> notice(10, None)

These commands are two equivalent ways of applying an open-ended notice filter to data in channel space. The lower limit of the filter is set to 10 channels, but the upper limit is undefined.

Example 4

sherpa> notice("0.1:5, 6:7")

Notice the data between 0.1 and 5 keV and between 6 and 7 keV.

Example 5

sherpa> notice(, 8.0)
sherpa> notice(None, 8.0)

These commands are two equivalent ways of applying an open-ended notice filter to data in energy space. The lower limit of the filter is undefined and the upper limit is set to 8.0 keV.


See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

get_filter, ignore, ignore2d, ignore2d_id, ignore_bad, ignore_id, notice2d, notice2d_id, notice_id, show_filter

Last modified: December 2010
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