Update on "[bug] [lang] Fix copyback for fortran contiguous numpy arr…

…ays" (#6390)"

Attempt #2
This PR got reverted due to failed release tests.

[ghstack-poisoned]

python/taichi/lang/field.py

@@ -347,6 +347,7 @@ def from_numpy(self, arr):
         """Copies the data from a `numpy.ndarray` into this field.
         """
         if not arr.flags.c_contiguous:
+            import numpy as np  # pylint: disable=C0415
             arr = np.ascontiguousarray(arr)
         self._from_external_arr(arr)
 

tests/python/test_numpy_io.py

@@ -160,3 +160,20 @@ def test_numpy_io_example():
     assert arr.shape == (n, m, 3, 4)
 
     # For PyTorch tensors, use to_torch/from_torch instead
+
+
+@test_utils.test(exclude=[ti.cc])
+def test_from_numpy_non_contiguous():
+    n = 9
+    m = 7
+    p = 4
+    arr = np.ones(shape=(n, m, p, p), dtype=np.int32)
+
+    val = ti.field(ti.i32, shape=(2, 2))
+    val.from_numpy(arr[0:6:3, 0:6:3, 0, 0])
+
+    vec = ti.Vector.field(3, dtype=ti.i32, shape=(2, 2))
+    vec.from_numpy(arr[0:6:3, 0:6:3, 0:3, 0])
+
+    mat = ti.Matrix.field(3, 4, dtype=ti.i32, shape=(2, 2))
+    mat.from_numpy(arr[0:6:3, 0:6:3, 0:3, 0:4])