Source code for pylops.basicoperators.roll

__all__ = ["Roll"]

from typing import Union

import numpy as np

from pylops import LinearOperator
from pylops.utils._internal import _value_or_sized_to_tuple
from pylops.utils.decorators import reshaped
from pylops.utils.typing import DTypeLike, InputDimsLike, NDArray

[docs]class Roll(LinearOperator): r"""Roll along an axis. Roll a multi-dimensional array along ``axis`` for a chosen number of samples (``shift``). Parameters ---------- dims : :obj:`list` or :obj:`int` Number of samples for each dimension axis : :obj:`int`, optional .. versionadded:: 2.0.0 Axis along which model is rolled. shift : :obj:`int`, optional Number of samples by which elements are shifted dtype : :obj:`str`, optional Type of elements in input array. name : :obj:`str`, optional .. versionadded:: 2.0.0 Name of operator (to be used by :func:`pylops.utils.describe.describe`) Attributes ---------- shape : :obj:`tuple` Operator shape explicit : :obj:`bool` Operator contains a matrix that can be solved explicitly (``True``) or not (``False``) Notes ----- The Roll operator is a thin wrapper around :func:`numpy.roll` and shifts elements in a multi-dimensional array along a specified direction for a chosen number of samples. """ def __init__( self, dims: Union[int, InputDimsLike], axis: int = -1, shift: int = 1, dtype: DTypeLike = "float64", name: str = "R", ) -> None: dims = _value_or_sized_to_tuple(dims) super().__init__(dtype=np.dtype(dtype), dims=dims, dimsd=dims, name=name) self.axis = axis self.shift = shift @reshaped(swapaxis=True) def _matvec(self, x: NDArray) -> NDArray: return np.roll(x, shift=self.shift, axis=-1) @reshaped(swapaxis=True) def _rmatvec(self, x: NDArray) -> NDArray: return np.roll(x, shift=-self.shift, axis=-1)