<h3 dir="auto">Issue with current documentation:</h3>
<p dir="auto">The documentation for scipy.interpolate.RegularGridInterpolator describes the class as for "Interpolation on a regular grid in arbitrary dimensions" and there is this statement, "The data must be defined on a regular grid; the grid spacing however may be uneven." Isn't such a grid a rectilinear grid, and not explicitly <em>not</em> a regular grid? See <a href="https://en.wikipedia.org/wiki/Regular_grid" rel="nofollow">Regular Grid</a>.</p>
<p dir="auto">The really odd thing about all of this is that the code on which this class is based, <em>regulargrid</em> by Johannes Buchner, seems to make the same mistake. In the README for the <a href="https://github.com/JohannesBuchner/regulargrid">regulargrid repo</a>, it even links the wikipedia article I've just referenced here at the top. Then it goes on to describe a Cartesian Grid as one with equal spacing between points (correct, but that spacing has to also be equal across each dimension) and a Regular Grid as having unequal spacing between points (incorrect). Beneath this definition of "Cartesian grid", there's an example of a grid which is Regular but not Cartesian.</p>
<p dir="auto">Just to make sure that the "Regular grid" was actually rectilinear, I checked regulargrid/test/test_regulargrid.py.  On line 13, the breaks are distributed randomly in each of two spatial dimensions, making it in fact rectilinear and not regular.</p>
<p dir="auto">I can also confirm that the same mistake is made in scipy.interpolate.interpn - I've used this code on rectilinear grids and it seems to work fine, despite the method saying that a "regular grid" is required many times in the documentation.</p>
<p dir="auto">I think correcting this is important - I tried for hours to find a rectilinear grid interpolator so that I could use it instead of interpn... it turns out I need not have bothered!</p>
<h3 dir="auto">Suggested fix:</h3>
<p dir="auto">The documentation for scipy.interpolate.RegularGridInterpolator and scipy.interpolate.interpn should be updated to specify that the interpolation happens on a rectilinear grid rather than a regular grid.</p>
<p dir="auto">The Pypi wheels (in particular the manylinux ones) contain prebuilts libraries for openblas (bsd) and libgfortran.... (gpl with runtime exception?)  but no information about their licenses and where to get the corresponding sources. It would be great to have some clarity in this domain.<br>
The same issue exists with numpy <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="210179946" data-permission-text="Title is private" data-url="https://github.com/numpy/numpy/issues/8689" data-hovercard-type="issue" data-hovercard-url="/numpy/numpy/issues/8689/hovercard" href="https://github.com/numpy/numpy/issues/8689">numpy/numpy#8689</a></p>