Last modified: December 2020

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/save_error.html
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AHELP for CIAO 4.13 Sherpa v1

save_error

Context: saving

Synopsis

Save the errors to a file.

Syntax

save_error(id, filename=None, bkg_id=None, ascii=True, clobber=False)

id - int or str, optional
filename - str
bkg_id - int or str, optional
ascii - bool, optional
clobber - bool, optional

Description

The total errors for a data set are the quadrature combination of the statistical and systematic errors. The systematic errors can be 0. If the statistical errors have not been set explicitly, then the values calculated by the statistic - such as chi2gehrels or chi2datavar - will be used.


Examples

Example 1

Write out the errors from the default data set to the file 'errs.dat'.

>>> save_error('errs.dat')

Example 2

Over-write the file it it already exists, and take the data from the data set "jet":

>>> save_error('jet', 'err.out', clobber=True)

Example 3

Write the data out in FITS format:

>>> save_error('err.fits', ascii=False)

PARAMETERS

The parameters for this function are:

Parameter Definition
id The identifier for the data set to use. If not given then the default identifier is used, as returned by `get_default_id` .
filename The name of the file to write the array to. The format is determined by the `ascii` argument.
bkg_id Set if the background should be written out rather than the source.
ascii If False then the data is written as a FITS format binary table. The default is True . The exact format of the output file depends on the I/O library in use (Crates or AstroPy).
clobber If `outfile` is not none , then this flag controls whether an existing file can be overwritten ( True ) or if it raises an exception ( False , the default setting).

Notes

The function does not follow the normal Python standards for parameter use, since it is designed for easy interactive use. When called with a single un-named argument, it is taken to be the `filename` parameter. If given two un-named arguments, then they are interpreted as the `id` and `filename` parameters, respectively. The remaining parameters are expected to be given as named arguments.

The output file contains the columns x and err .


Bugs

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

See Also

contrib
save_chart_spectrum, save_marx_spectrum
data
copy_data, dataspace1d, dataspace2d, datastack, delete_data, fake, get_axes, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_source_plot, get_counts, get_data, get_data_contour, get_data_contour_prefs, get_data_image, get_data_plot, get_data_plot_prefs, get_dep, get_dims, get_error, get_quality, get_specresp, get_staterror, get_syserror, group, group_adapt, group_adapt_snr, group_bins, group_counts, group_snr, group_width, load_arf, load_arrays, load_ascii, load_bkg, load_bkg_arf, load_bkg_rmf, load_data, load_grouping, load_image, load_multi_arfs, load_multi_rmfs, load_pha, load_quality, load_rmf, load_staterror, load_syserror, load_table, pack_image, pack_pha, pack_table, set_data, set_quality, ungroup, unpack_arf, unpack_arrays, unpack_ascii, unpack_bkg, unpack_data, unpack_image, unpack_pha, unpack_rmf, unpack_table
filtering
get_filter, load_filter, set_filter
info
get_default_id, list_bkg_ids, list_data_ids, list_response_ids
modeling
add_model, add_user_pars, clean, load_table_model, load_template_interpolator, load_template_model, load_user_model, save_model, save_source
plotting
plot_data, set_xlinear, set_xlog, set_ylinear, set_ylog
saving
restore, save, save_all, save_arrays, save_data, save_delchi, save_filter, save_grouping, save_image, save_pha, save_quality, save_resid, save_staterror, save_syserror, save_table, script
statistics
load_user_stat
utilities
calc_data_sum, calc_data_sum2d, calc_ftest, calc_kcorr, calc_mlr, calc_model_sum2d, calc_source_sum2d, get_rate
visualization
contour, contour_data, contour_ratio, histogram1d, histogram2d, image_data, rebin