def ix_(*args):
"""Construct an open mesh from multiple sequences.
This function takes N 1-D sequences and returns N outputs with N
dimensions each, such that the shape is 1 in all but one dimension
and the dimension with the non-unit shape value cycles through all
N dimensions.
Using `ix_` one can quickly construct index arrays that will index
the cross product. ``a[cupy.ix_([1,3],[2,5])]`` returns the array
``[[a[1,2] a[1,5]], [a[3,2] a[3,5]]]``.
Args:
*args: 1-D sequences
Returns:
tuple of ndarrays:
N arrays with N dimensions each, with N the number of input sequences.
Together these arrays form an open mesh.
Examples
--------
>>> a = cupy.arange(10).reshape(2, 5)
>>> a
array([[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]])
>>> ixgrid = cupy.ix_([0,1], [2,4])
>>> ixgrid
(array([[0],
[1]]), array([[2, 4]]))
.. warning::
This function may synchronize the device.
.. seealso:: :func:`numpy.ix_`
"""
# TODO(niboshi): Avoid nonzero which may synchronize the device.
out = []
nd = len(args)
for k, new in enumerate(args):
new = from_data.asarray(new)
if new.ndim != 1:
raise ValueError('Cross index must be 1 dimensional')
if new.size == 0:
# Explicitly type empty arrays to avoid float default
new = new.astype(numpy.intp)
if cupy.issubdtype(new.dtype, cupy.bool_):
new, = new.nonzero() # may synchronize
new = new.reshape((1,) * k + (new.size,) + (1,) * (nd - k - 1))
out.append(new)
return tuple(out)
def ix_(*args):
"""Construct an open mesh from multiple sequences.
This function takes N 1-D sequences and returns N outputs with N
dimensions each, such that the shape is 1 in all but one dimension
and the dimension with the non-unit shape value cycles through all
N dimensions.
Using `ix_` one can quickly construct index arrays that will index
the cross product. ``a[cupy.ix_([1,3],[2,5])]`` returns the array
``[[a[1,2] a[1,5]], [a[3,2] a[3,5]]]``.
Args:
*args: 1-D sequences
Returns:
tuple of ndarrays:
N arrays with N dimensions each, with N the number of input sequences.
Together these arrays form an open mesh.
Examples
--------
>>> a = cupy.arange(10).reshape(2, 5)
>>> a
array([[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]])
>>> ixgrid = cupy.ix_([0,1], [2,4])
>>> ixgrid
(array([[0],
[1]]), array([[2, 4]]))
.. seealso:: :func:`numpy.ix_`
"""
out = []
nd = len(args)
for k, new in enumerate(args):
new = from_data.asarray(new)
if new.ndim != 1:
raise ValueError("Cross index must be 1 dimensional")
if new.size == 0:
# Explicitly type empty arrays to avoid float default
new = new.astype(numpy.intp)
if cupy.issubdtype(new.dtype, cupy.bool_):
new, = new.nonzero()
new = new.reshape((1,) * k + (new.size,) + (1,) * (nd - k - 1))
out.append(new)
return tuple(out)
