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])

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.

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.

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
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info: list_model_ids, show_bkg_model, show_bkg_source
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