provide info in doc and write an example page

[Tieqiong]

Add information on the documentation page.

I moved doc/examples into doc/source/examples and add an example page. I merged Ni_plot_pdf and Ni_calculation because they are mostly the same. I also update pylab plots to pyplot because The use of pylab is discouraged now

[sbillinge]

Please see inline comments. The examples send to be mostly the example code copy-pasted into the rst. See if there is an automatic way of doing that, but if not, please redo it to reflect the latest updated code.

[Tieqiong]

Please see inline comments. The examples send to be mostly the example code copy-pasted into the rst. See if there is an automatic way of doing that, but if not, please redo it to reflect the latest updated code.

I can write a python code for automating this process, but it's not necessary for this package because examples are kind of short. Ideally we can set a fixed template and conventions for example files and write a python code and put into the release-script repo. It could be helpful for other packages that have long examples

[sbillinge]

Thanks for this. Please check the examples.rst in the docs. Does it still contain the old code or am I looking at an out of date version?

[Tieqiong]

@sbillinge It's the updated version. Also I can make a issue in release script if we want to have the automated example builder.

[sbillinge]

I see this in the example docs but didn't we move away from using pylab?
. We can also plot it using matplotlib::

import matplotlib.pyplot as plt

# obtain list of r-points and corresponding G values
r = P.getR()
G = P.getpdf_fit()

plt.plot(r, G)
pylab.xlabel("r (Å)")
pylab.ylabel("G (Å$^{-2}$)")
pylab.title("x-ray PDF of nickel simulated at Qmax = %g" % qmax)

# display plot window, this must be the last command in the script
pylab.show()

[Tieqiong]

I see this in the example docs but didn't we move away from using pylab? . We can also plot it using matplotlib::

import matplotlib.pyplot as plt

# obtain list of r-points and corresponding G values
r = P.getR()
G = P.getpdf_fit()

plt.plot(r, G)
pylab.xlabel("r (Å)")
pylab.ylabel("G (Å$^{-2}$)")
pylab.title("x-ray PDF of nickel simulated at Qmax = %g" % qmax)

# display plot window, this must be the last command in the script
pylab.show()

Yes thanks for the catch! sorry for the oversight

[sbillinge]

please could you make sure that the code in the docs works and let me know? I think copy-pasting the working code is maybe the best approach but I leave it up to you.