cupy.isfortran¶

cupy.isfortran(a)[source]

Returns True if the array is Fortran contiguous but not C contiguous.

If you only want to check if an array is Fortran contiguous use a.flags.f_contiguous instead.

Parameters: a (cupy.ndarray) – Input array. The return value, True if a is Fortran contiguous but not C contiguous. bool

Examples

cupy.array allows to specify whether the array is written in C-contiguous order (last index varies the fastest), or FORTRAN-contiguous order in memory (first index varies the fastest).

>>> a = cupy.array([[1, 2, 3], [4, 5, 6]], order='C')
>>> a
array([[1, 2, 3],
[4, 5, 6]])
>>> cupy.isfortran(a)
False

>>> b = cupy.array([[1, 2, 3], [4, 5, 6]], order='F')
>>> b
array([[1, 2, 3],
[4, 5, 6]])
>>> cupy.isfortran(b)
True


The transpose of a C-ordered array is a FORTRAN-ordered array.

>>> a = cupy.array([[1, 2, 3], [4, 5, 6]], order='C')
>>> a
array([[1, 2, 3],
[4, 5, 6]])
>>> cupy.isfortran(a)
False
>>> b = a.T
>>> b
array([[1, 4],
[2, 5],
[3, 6]])
>>> cupy.isfortran(b)
True


C-ordered arrays evaluate as False even if they are also FORTRAN-ordered.

>>> cupy.isfortran(np.array([1, 2], order='F'))
False