Skip to content

nxdata stricter suggestion on when axisname indices can be omitted + clarify 3D or higher #1550

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
woutdenolf wants to merge 3 commits into
base: main
Choose a base branch
from
Open

nxdata stricter suggestion on when axisname indices can be omitted + clarify 3D or higher #1550

Changes from 2 commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
406b742
omitting AXISNAME_indices can only be unambiguous in the case of 1D axes
woutdenolf Mar 12, 2025
975c349
make clear that 3- or higher-dimensions are allowed for data and axes
woutdenolf Mar 12, 2025
a778dfe
use "equally" instead of "equivalently"
woutdenolf Mar 18, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 8 additions & 7 deletions base_classes/NXdata.nxdl.xml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -75,11 +75,12 @@

More complex cases are supported

* histogram data: ``x`` has one more value than ``data``.
* alternative axes: instead of a single ``x`` axis you can have several axes, one of which being the default.
* signals with more than one dimension: ``data`` could be 2D with axes ``x`` and ``y`` along each dimension.
* axes with more than one dimension: ``data`` could be 2D with axes ``x`` and ``y`` also being 2D, providing a
unique ``(x, y)`` coordinate for each ``data`` point.
* Histogram data. For example ``x`` has one more value than ``data``.
* Alternative axes. For example instead of a single ``x`` axis you can have several axes, one of which being the default.
* Signals with more than one dimension. For example ``data`` could be 2D with axes ``x`` and ``y`` along each dimension.
Equivalently 3- or higher-dimensional data is allowed.
Comment thread
woutdenolf marked this conversation as resolved.
Outdated
* Axes with more than one dimension. For example ``data`` could be 2D with axes ``x`` and ``y`` also being 2D, providing a
unique ``(x, y)`` coordinate for each ``data`` point. Equivalently 3- or higher-dimensional axes are allowed.
Copy link
Copy Markdown
Contributor Author

@woutdenolf woutdenolf Mar 12, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Addresses @rayosborn comment #1396 (review)

Copy link
Copy Markdown
Contributor Author

@woutdenolf woutdenolf Mar 12, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

For reference: the examples could give the impression NXdata only support 1D and 2D data.

Solved by

  • Clearly prepend with "For example"
  • Add "Equivalently 3- or higher-dimensional data is allowed" and "Equivalently 3- or higher-dimensional axes are allowed"


**Signals:**

Expand Down Expand Up @@ -141,8 +142,8 @@
field name in the :ref:`axes </NXdata@axes-attribute>` attribute are used.

4. When :ref:`AXISNAME_indices </NXdata@AXISNAME_indices-attribute>` is the same as the indices of "AXISNAME" in the
:ref:`axes </NXdata@axes-attribute>` attribute, there is no need to provide
:ref:`AXISNAME_indices </NXdata@AXISNAME_indices-attribute>`.
:ref:`axes </NXdata@axes-attribute>` attribute and :ref:`AXISNAME </NXdata/AXISNAME-field>` is one-dimensional,
the :ref:`AXISNAME_indices </NXdata@AXISNAME_indices-attribute>` attribute can be omitted.
Comment on lines +145 to +146
Copy link
Copy Markdown
Contributor Author

@woutdenolf woutdenolf Mar 12, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Addresses @PeterC-DLS comment #1396 (comment)

Copy link
Copy Markdown
Contributor Author

@woutdenolf woutdenolf Mar 12, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

For reference: for higher dimensional axes the AXISNAME_indices attribute can never be omitted unambiguously by using the indices in @axes instead. For example @axes=["x", "x", "z"] could be @x_indices=[0,1] or @x_indices=[1,0].

Copy link
Copy Markdown
Contributor

@PeterC-DLS PeterC-DLS Mar 13, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

That is a bit too strong as you could determine the indices ordering from the signal field shape if the pertinent dimensions are distinct: in the example, signal[23,47,17] with x[47,23] is unambigously inferred to have @x_indices=[1,0].

Copy link
Copy Markdown
Contributor Author

@woutdenolf woutdenolf Mar 18, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Sure it can be omitted for nD if it can be derived "unambigously". But then to define what "unambigously" means in this context would be rather convoluted. For example it won't work when signal[23,23,17].

So your original suggestion to omit AXISNAME_indices only for 1D still makes sense imo.


5. The indices of "AXISNAME" in the :ref:`axes </NXdata@axes-attribute>` attribute must be a subset of
:ref:`AXISNAME_indices </NXdata@AXISNAME_indices-attribute>`.
Expand Down