Last modified: December 2020

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/histogram2d.html
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AHELP for CIAO 4.13 Sherpa v1

histogram2d

Context: visualization

Synopsis

Create 2D histogram from a sequence of samples.

Syntax

histogram2d(x, y, x_grid, y_grid)

x - sequence of numbers
y - sequence of numbers
x_grid - sequence of numbers
y_grid - sequence of numbers

Description

See the `numpy.histogram2d` routine for a version with more options.


Example

Given a list of coordinates ( xvals , yvals ), bin them up so that they match the 5 by 10 pixel image data space. In this case the X grid is [1, 2, ..., 5] and the Y grid is [1, 2, .., 10].

>>> dataspace2d([5, 10])
>>> (xgrid, ygrid) = get_axes()
>>> n = histogram2d(xvals, yvals, xgrid, ygrid)
>>> set_dep(n)

PARAMETERS

The parameters for this function are:

Parameter Definition
x The array of samples (X coordinate)
y The array of samples (Y coordinate), which must have the same size as the x sequence.
x_grid The X bin edges.
y_grid The Y bin edges.

Return value

The return value from this function is:

y -- The number of samples in each histogram bin defined by the x_grid and y_grid arrays.


Bugs

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

See Also

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_ascii, load_data, load_grouping, load_quality, set_data, set_quality, ungroup, unpack_ascii, unpack_data
filtering
get_filter, load_filter, set_filter
info
get_default_id, list_data_ids, list_response_ids
modeling
clean
plotting
plot_data, set_xlinear, set_xlog, set_ylinear, set_ylog
saving
save_error, save_filter, save_grouping, save_quality, save_staterror, save_syserror
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, image_data, rebin