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Last modified: December 2014

URL: http://cxc.harvard.edu/sherpa/ahelp/plot_cdf.html
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AHELP for CIAO 4.9 Sherpa v1

plot_cdf

Context: plotting

Synopsis

Plot a cumulative distribution function with lower, median, and upper quantiles.

Syntax

plot_cdf(points [, name="x", xlabel="x", replot=False, overplot=False,
clearwindow=True])

Description

The plot_cdf() function plots the cumulative probability distribution function (cdf) of a specified array of histogram values (a NumPY ndarray), with the given plot title and x-axis label (default is "x" for each). The median and upper/lower quantiles are marked by orange and blue, vertical, dashed lines, respectively. The upper- and lower-bounds are the 1-sigma bounds (68.2689%).

Argument Default Description
points NumPy ndarray of histogram data values
name "x" title to assign to the plot
xlabel "x" label to assign to the x-axis
replot False Should previously-calculated arrays be used to create the plot?
overplot False If True, then add the data to the current plot, otherwise erase the frame and create a new plot.
clearwindow True If True, then do not delete any existing frames in the current ChIPS window. Note that the plots will be created in a new ChIPS frame even when this argument is set.

Example 1

plot_cdf(x)

Define a histogram in the variable "x" and plot the corresponding cumulative probability density function with default settings.

sherpa> import numpy as np
sherpa> mu, sigma = 100, 15
sherpa> x = mu + sigma*np.random.randn(10000)
sherpa> plot_cdf(x)

Example 2

plot_cdf(x, name="Energy Flux CDF", xlabel="flux")

Plot the cumulative density function for a simulated energy flux distribution returned by the sample_energy_flux() command (see 'ahelp sample_energy_flux'), using a custom plot title and x-axis label.

sherpa> a = sample_energy_flux(0.5,7.,num=1000)
sherpa> plot_energy_flux()
sherpa> x = a[:,0]
sherpa> plot_cdf(x, name="Energy Flux CDF", xlabel="flux")

Bugs

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

See Also

contrib
get_data_prof, get_data_prof_prefs, get_delchi_prof, get_delchi_prof_prefs, get_fit_prof, get_model_prof, get_model_prof_prefs, get_resid_prof, get_resid_prof_prefs, get_source_prof, get_source_prof_prefs, plot_chart_spectrum, prof_data, prof_delchi, prof_fit, prof_fit_delchi, prof_fit_resid, prof_model, prof_resid, prof_source
data
get_arf_plot, get_bkg_plot
info
list_model_ids, show_bkg_model, show_bkg_source
modeling
add_model, add_user_pars, clean, create_model_component, delete_bkg_model, delete_model, delete_model_component, get_model, get_model_autoassign_func, get_model_component, get_model_component_image, get_model_component_plot, get_model_plot, get_num_par, get_order_plot, get_par, get_pileup_model, get_source, get_source_component_image, get_source_component_plot, image_model, image_model_component, image_source, image_source_component, integrate, integrate1d, link, load_table_model, load_template_model, load_user_model, normal_sample, reset, save_model, save_source, set_bkg_model, set_full_model, set_model_autoassign_func, set_pileup_model, set_source, set_xsabund, set_xscosmo, set_xsxsect, set_xsxset, t_sample, uniform_sample
plotting
get_energy_flux_hist, get_lrt_plot, get_lrt_results, get_photon_flux_hist, get_pvalue_plot, get_pvalue_results, get_split_plot, plot, plot_arf, plot_bkg, plot_chisqr, plot_data, plot_delchi, plot_energy_flux, plot_fit, plot_model, plot_model_component, plot_order, plot_pdf, plot_photon_flux, plot_pvalue, plot_ratio, plot_resid, plot_scatter, plot_source, plot_source_component, plot_trace, set_xlinear, set_xlog, set_ylinear, set_ylog
psfs
delete_psf, load_conv, plot_kernel
saving
save_delchi, save_resid
statistics
get_chisqr_plot, get_delchi_plot
utilities
calc_chisqr, calc_energy_flux, calc_model_sum, calc_photon_flux, calc_source_sum, calc_stat, eqwidth
visualization
contour_model, contour_ratio, contour_resid, get_ratio, get_resid

Last modified: December 2014
Smithsonian Institute Smithsonian Institute

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email:   cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2017. All rights reserved.