Clarify MR data views in the case of numpy version 1.* (#1366)

Clarify in documentation and test cases that numpy 2 is required for some functionality.

Author: evgueni-ovtchinnikov

CHANGES.md

@@ -22,10 +22,11 @@
     - `ImageData` and `AcquisitionDataInMemory` have `supports_array_view==True`
 
 * SIRF/Gadgetron
-  - `ImageDataView` and `AcquisitionDataView` classes implemented that encapsulate arrays of NumPy views of `ISMRMRD_ImageData` and `ISMRMRD_AcquisitionData` objects respectively, significantly accelerating the algebraic operations (up to a factor of about 10 for images).
+  - `ImageDataView` and `AcquisitionDataView` classes implemented that encapsulate arrays of NumPy views of `ISMRMRD_ImageData` and `ISMRMRD_AcquisitionData` objects respectively, significantly accelerating the algebraic operations (up to a factor of about 10 for images). As these classes require numpy version major being not less than 2, tests that use them are skipped if this requirement is not met.
 
 * SIRF/Registration
   - Nifty images have `supports_array_view==True`
+  - PET/Registration `ImageData` and PET `AcquisitionData` have `.asarray(copy=False)` (NumPy-like behaviour: default zero-copy if contiguous, fallback to deepcopy otherwise) via `__array_interface__`.
 
 * CI and testing
   - made tests return value handling compatible with a future version of pytest.

examples/Python/MR/data_views.py

@@ -11,6 +11,13 @@
 
 {licence}
 """
+
+import numpy
+numpy_major = int(numpy.__version__[0])
+if numpy_major < 2:
+    print('Using data views requires numpy version major not less than 2, exiting.')
+    exit()
+
 from sirf.SIRF import norm, dot, copyto
 from sirf.Gadgetron import AcquisitionData, \
     AcquisitionDataView, ImageDataView, FullySampledReconstructor

examples/Python/MR/mr_timings.py

@@ -19,6 +19,11 @@
 """
 
 import numpy
+numpy_major = int(numpy.__version__[0])
+if numpy_major < 2:
+    print('Using data views requires numpy version major not less than 2, exiting.')
+    exit()
+
 import timeit
 import importlib