The NXdata definition got a makeover in PR #1213 to make it more understandable. In this effort, the @axes attribute was made less restrictive to allow for an unambiguous discovery of axis fields. This does not make existing files invalid but it does change things for existing readers as pointed out in issue #1381 by @jacobfilik .
The sole purpose of this PR is to rectify PR #1213 and NOT introduce anything new. The alternative PR https://github.com/nexusformat/definitions/pull/1392 by @PeterC-DLS fixes the situation by carefully modifying some sentences here and there. I would argue however that the entire "axes" section in the introduction has been structured with the less restrictive @axes in mind. In this PR I refactor the entire "axes" section as well as make @axes restrictive again.
FYI the less restrictive @axes attribute definition
The `@axes` attribute provides the names of all the `AXISNAME` fields in the NXdata group.
The corresponding `@AXISNAME_indices` attributes provide the signal dimensions they span
and when missing the position(s) of `AXISNAME` in `@axes` are taken as the signal dimensions
spanned by `AXISNAME`. The shape of an `AXISNAME` field is required to be equal to the shape
of the spanned signal dimensions.
This definition is much simpler and more concise than the definition in the "axes" section in the PR. However it removes the restriction that length(axes) == rank(signal) so we need to put it back in with @axes being the default axes, not all axes.
When reviewing this PR, please keep in mind that the purpose is to rectify NXdata, not improve it. Use #1381 for that.
Closes #1381
HTML RENDERING OF NXDATA FIX <-> current nxdata for comparison
The NXdata definition got a makeover in PR #1213 to make it more understandable. In this effort, the
@axesattribute was made less restrictive to allow for an unambiguous discovery of axis fields. This does not make existing files invalid but it does change things for existing readers as pointed out in issue #1381 by @jacobfilik .The sole purpose of this PR is to rectify PR #1213 and NOT introduce anything new. The alternative PR https://github.com/nexusformat/definitions/pull/1392 by @PeterC-DLS fixes the situation by carefully modifying some sentences here and there. I would argue however that the entire "axes" section in the introduction has been structured with the less restrictive
@axesin mind. In this PR I refactor the entire "axes" section as well as make@axesrestrictive again.FYI the less restrictive
@axesattribute definitionThis definition is much simpler and more concise than the definition in the "axes" section in the PR. However it removes the restriction that
length(axes) == rank(signal)so we need to put it back in with @axes being the default axes, not all axes.When reviewing this PR, please keep in mind that the purpose is to rectify NXdata, not improve it. Use #1381 for that.