def shift(input,
shift,
output=None,
order=3,
mode='constant',
cval=0.0,
prefilter=True):
"""Shift an array.
The array is shifted using spline interpolation of the requested order.
Points outside the boundaries of the input are filled according to the
given mode.
Args:
input (cupy.ndarray): The input array.
shift (float or sequence): The shift along the axes. If a float,
``shift`` is the same for each axis. If a sequence, ``shift``
should contain one value for each axis.
output (cupy.ndarray or ~cupy.dtype): The array in which to place the
output, or the dtype of the returned array.
order (int): The order of the spline interpolation, default is 3. Must
be in the range 0-5.
mode (str): Points outside the boundaries of the input are filled
according to the given mode (``'constant'``, ``'nearest'``,
``'mirror'``, ``'reflect'``, ``'wrap'``, ``'grid-mirror'``,
``'grid-wrap'``, ``'grid-constant'`` or ``'opencv'``).
cval (scalar): Value used for points outside the boundaries of
the input if ``mode='constant'`` or ``mode='opencv'``. Default is
0.0
prefilter (bool): It is not used yet. It just exists for compatibility
with :mod:`scipy.ndimage`.
Returns:
cupy.ndarray or None:
The shifted input.
.. seealso:: :func:`scipy.ndimage.shift`
"""
_check_parameter('shift', order, mode)
shift = _util._fix_sequence_arg(shift, input.ndim, 'shift', float)
if mode == 'opencv':
mode = '_opencv_edge'
output = affine_transform(
input,
cupy.ones(input.ndim, input.dtype),
cupy.negative(cupy.asarray(shift)),
None,
output,
order,
mode,
cval,
prefilter,
)
else:
output = _util._get_output(output, input)
if input.dtype.kind in 'iu':
input = input.astype(cupy.float32)
filtered, nprepad = _filter_input(input, prefilter, mode, cval, order)
integer_output = output.dtype.kind in 'iu'
_util._check_cval(mode, cval, integer_output)
large_int = _prod(input.shape) > 1 << 31
kern = _interp_kernels._get_shift_kernel(input.ndim,
large_int,
input.shape,
mode,
cval=cval,
order=order,
integer_output=integer_output,
nprepad=nprepad)
shift = cupy.asarray(shift, dtype=cupy.float64, order='C')
if shift.ndim != 1:
raise ValueError('shift must be 1d')
if shift.size != filtered.ndim:
raise ValueError('len(shift) must equal input.ndim')
kern(filtered, shift, output)
return output
def shift(input,
shift,
output=None,
order=None,
mode='constant',
cval=0.0,
prefilter=True):
"""Shift an array.
The array is shifted using spline interpolation of the requested order.
Points outside the boundaries of the input are filled according to the
given mode.
Args:
input (cupy.ndarray): The input array.
shift (float or sequence): The shift along the axes. If a float,
``shift`` is the same for each axis. If a sequence, ``shift``
should contain one value for each axis.
output (cupy.ndarray or ~cupy.dtype): The array in which to place the
output, or the dtype of the returned array.
order (int): The order of the spline interpolation. If it is not given,
order 1 is used. It is different from :mod:`scipy.ndimage` and can
change in the future. Currently it supports only order 0 and 1.
mode (str): Points outside the boundaries of the input are filled
according to the given mode (``'constant'``, ``'nearest'``,
``'mirror'`` or ``'opencv'``). Default is ``'constant'``.
cval (scalar): Value used for points outside the boundaries of
the input if ``mode='constant'`` or ``mode='opencv'``. Default is
0.0
prefilter (bool): It is not used yet. It just exists for compatibility
with :mod:`scipy.ndimage`.
Returns:
cupy.ndarray or None:
The shifted input.
.. seealso:: :func:`scipy.ndimage.shift`
"""
_check_parameter('shift', order, mode)
if not hasattr(shift, '__iter__') and type(shift) is not cupy.ndarray:
shift = [shift] * input.ndim
if mode == 'opencv':
mode = '_opencv_edge'
output = affine_transform(
input,
cupy.ones(input.ndim, input.dtype),
cupy.negative(cupy.asarray(shift)),
None,
output,
order,
mode,
cval,
prefilter,
)
else:
if order is None:
order = 1
output = _get_output(output, input)
if input.dtype.kind in 'iu':
input = input.astype(cupy.float32)
integer_output = output.dtype.kind in 'iu'
large_int = _prod(input.shape) > 1 << 31
kern = _interp_kernels._get_shift_kernel(input.ndim,
large_int,
input.shape,
mode,
cval=cval,
order=order,
integer_output=integer_output)
shift = cupy.asarray(shift, dtype=cupy.float64)
kern(input, shift, output)
return output