brahmap.lbsim.LBSimSharedMemProcessTimeSamples

Bases: SharedMemProcessTimeSamples

An MPI shared memory data container to store the pre-processed and pre-computed arrays and metadata from litebird_sim observations.

Similar to LBSimProcessTimeSamples, this container object can be used to create pointing operators, block-diagonal preconditioners, etc. as required for map-making, but using MPI shared memory to reduce the memory footprint.

Parameters:

Name	Type	Description	Default
nside	int	The HEALPix \(N_{side}\) resolution parameter defining the number of pixels	required
observations	Observation | List[Observation]	An instance of the Observation class or a list of the same	required
pointings	NDArray[number] | List[NDArray[number]] | None	Array of detector pointing indices mapping time samples to observed sky pixels, by default None	None
hwp	HWP | None	The Half-Wave Plate (HWP) angles or configuration, by default None	None
pointings_flag	NDArray[bool_] | None	Boolean array indicating valid pointing samples, by default None. The True value indicates a valid pointing, and the False value indicates a bad pointing. If set as None, all the pointings are considered valid	None
solver_type	SolverType	The level of map-making solver to construct (\(I\), \(QU\), or \(IQU\)), by default SolverType.IQU	IQU
noise_weights	NDArray[number] | None	Array of noise inverse noise variance for each time sample, by default None. If set as None, inverse noise variance is set to 1 for each time sample	None
output_coordinate_system	CoordinateSystem	The celestial coordinate system to use for the generated output maps, by default lbs.CoordinateSystem.Galactic	Galactic
threshold	float	The condition number threshold used to flag degenerate or under-sampled pixels, by default 1.0e-5	1e-05
dtype_float	DTypeFloat	The data type to use for floating point arrays, by default np.float64	float64
nproc_reduce	int	Number of processes used in parallel Reduction within nodes for shared memory mode. See SharedMemProcessTimeSamples for more details. By default 1	1

Methods:

Name	Description
get_hit_counts	Returns hit counts of the pixel indices.
free_shmem_arrays	Frees all allocated shared-memory arrays and windows.

Attributes:

Name	Type	Description
npix	int	Number of pixels on which the map-making has to be done.
pointings	NDArray[integer]	A 1-d array of pixel indices pointing to the observed sky pixel
pointings_flag	NDArray[bool_] | None	A 1-d boolean array where True indicates a valid pointing and
nsamples	int	The number of time samples processed by the current MPI rank
nsamples_global	int	The total number of time samples across all MPI ranks
solver_type	SolverType	The current map-making solver configuration (\(I\), \(QU\), or \(IQU\))
threshold	float	The condition number threshold used to flag bad pixels
dtype_float	Any	The inferred or specified data type for floating point arrays
observed_pixels	NDArray[integer]	A 1-d array containing the original indices of the pixels that
pixel_flag	NDArray[bool_]	A 1-d boolean array of size npix where True indicates a bad
bad_pixels	NDArray[integer]	A 1-d array that contains all the pixel indices that will be excluded
old2new_pixel	NDArray[integer]	A 1-d array mapping old pixel indices to new pixel indices
weighted_counts	NDArray[number]	A 1-d array accumulating the inverse noise weights per valid pixel
sin2phi	NDArray[number]	A 1-d array containing \(\sin(2\phi)\) evaluated at the valid time samples
cos2phi	NDArray[number]	A 1-d array containing \(\cos(2\phi)\) evaluated at the valid time samples
weighted_sin	NDArray[number]	A 1-d array accumulating the noise-weighted \(\sin(2\phi)\) sum
weighted_cos	NDArray[number]	A 1-d array accumulating the noise-weighted \(\cos(2\phi)\) sum
weighted_sin_sq	NDArray[number]	A 1-d array accumulating the noise-weighted \(\sin^2(2\phi)\) sum
weighted_cos_sq	NDArray[number]	A 1-d array accumulating the noise-weighted \(\cos^2(2\phi)\) sum
weighted_sincos	NDArray[number]	A 1-d array accumulating the noise-weighted \(\sin(2\phi)\cos(2\phi)\)
one_over_determinant	NDArray[number]	A 1-d array containing the inverse determinant of the
new_npix	int	The number of pixels on which the map-making will be done
nproc_reduce	int	The size of each sub-communicator group within the node-level
shared_mem_root	int	The designated root rank within the node-level shared memory
shared_mem_manager	SharedMemoryManager	The manager class for MPI shared-memory communicators and windows
obs_list	list[Observation]	A list of the parsed litebird_sim observations.
nside	int	The HEALPix resolution parameter.
coordinate_system	CoordinateSystem	The output celestial coordinate system used in data processing.

Source code in brahmap/lbsim/lbsim_process_time_samples.py

class LBSimSharedMemProcessTimeSamples(SharedMemProcessTimeSamples):
    """An MPI shared memory data container to store the pre-processed and
    pre-computed arrays and metadata from `litebird_sim` observations.

    Similar to [`LBSimProcessTimeSamples`][brahmap.lbsim.LBSimProcessTimeSamples],
    this container object can be used to create pointing operators,
    block-diagonal preconditioners, etc. as required for map-making, but
    using MPI shared memory to reduce the memory footprint.

    Parameters
    ----------
    nside : int
        The HEALPix $N_{side}$ resolution parameter defining the number of pixels
    observations : lbs.Observation | List[lbs.Observation]
        An instance of the `Observation` class or a list of the same
    pointings : npt.NDArray[np.number] | List[npt.NDArray[np.number]] | None, optional
        Array of detector pointing indices mapping time samples to observed
        sky pixels, by default `None`
    hwp : lbs.HWP | None, optional
        The Half-Wave Plate (HWP) angles or configuration, by default `None`
    pointings_flag : npt.NDArray[np.bool_] | None, optional
        Boolean array indicating valid pointing samples, by default `None`.
        The `True` value indicates a valid pointing, and the `False`
        value indicates a bad pointing. If set as `None`, all the
        pointings are considered valid
    solver_type : SolverType, optional
        The level of map-making solver to construct ($I$, $QU$, or
        $IQU$), by default `SolverType.IQU`
    noise_weights : npt.NDArray[np.number] | None, optional
        Array of noise inverse noise variance for each time sample, by
        default `None`. If set as `None`, inverse noise variance is set to 1 for each time sample
    output_coordinate_system : lbs.CoordinateSystem, optional
        The celestial coordinate system to use for the generated output maps,
        by default `lbs.CoordinateSystem.Galactic`
    threshold : float, optional
        The condition number threshold used to flag degenerate or under-sampled
        pixels, by default `1.0e-5`
    dtype_float : DTypeFloat, optional
        The data type to use for floating point arrays, by default
        `np.float64`
    nproc_reduce : int, optional
        Number of processes used in parallel Reduction within nodes for shared memory mode. See
        [`SharedMemProcessTimeSamples`][brahmap.core.SharedMemProcessTimeSamples]
        for more details. By default `1`
    """

    def __init__(
        self,
        nside: int,
        observations: lbs.Observation | List[lbs.Observation],
        pointings: npt.NDArray[np.number] | List[npt.NDArray[np.number]] | None = None,
        hwp: lbs.HWP | None = None,
        pointings_flag: npt.NDArray[np.bool_] | None = None,
        solver_type: SolverType = SolverType.IQU,
        noise_weights: npt.NDArray[np.number] | None = None,
        output_coordinate_system: lbs.CoordinateSystem = lbs.CoordinateSystem.Galactic,
        threshold: float = 1.0e-5,
        dtype_float: DTypeFloat = np.float64,
        nproc_reduce: int = 1,
    ) -> None:
        self.__nside = nside
        self.__coordinate_system = output_coordinate_system
        npix = hp.nside2npix(self.nside)

        self.__obs_list, pix_indices, pol_angles = _process_lbsim_observations(
            nside=nside,
            observations=observations,
            pointings=pointings,
            hwp=hwp,
            output_coordinate_system=output_coordinate_system,
            dtype_float=dtype_float,
        )

        super().__init__(
            npix=npix,
            pointings=pix_indices,
            pointings_flag=pointings_flag,
            solver_type=solver_type,
            pol_angles=pol_angles,
            noise_weights=noise_weights,
            threshold=threshold,
            dtype_float=dtype_float,
            update_pointings_inplace=True,
            nproc_reduce=nproc_reduce,
        )

    @property
    def obs_list(self) -> List[lbs.Observation]:
        """A list of the parsed `litebird_sim` observations.

        Returns
        -------
        List[lbs.Observation]
            The list of observations
        """
        return self.__obs_list

    @property
    def nside(self) -> int:
        """The HEALPix resolution parameter.

        Returns
        -------
        int
            The $N_{side}$ parameter
        """
        return self.__nside

    @property
    def coordinate_system(self) -> lbs.CoordinateSystem:
        """The output celestial coordinate system used in data processing.

        Returns
        -------
        lbs.CoordinateSystem
            The configured coordinate system
        """
        return self.__coordinate_system

Attributes

npix: int property

Number of pixels on which the map-making has to be done.

Returns:

Type	Description
int	Number of pixels on which the map-making has to be done

pointings: npt.NDArray[np.integer] property

A 1-d array of pixel indices pointing to the observed sky pixel for each time sample

Returns:

Type	Description
NDArray[integer]	A 1-d array of pixel pointing indices for each time sample

pointings_flag: npt.NDArray[np.bool_] | None property

A 1-d boolean array where True indicates a valid pointing and False flags a bad pointing

Returns:

Type	Description
NDArray[bool_]	The 1-d array of flags indicating valid (True) or discarded
(`False`) time samples

nsamples: int property

The number of time samples processed by the current MPI rank

Returns:

Type	Description
int	Number of samples on current MPI rank

nsamples_global: int property

The total number of time samples across all MPI ranks

Returns:

Type	Description
int	Global number of samples

solver_type: SolverType property

The current map-making solver configuration (\(I\), \(QU\), or \(IQU\))

Returns:

Type	Description
SolverType	Level of map-making: \(I\), \(QU\), or \(IQU\)

threshold: float property

The condition number threshold used to flag bad pixels

Returns:

Type	Description
float	Threshold to used for flagging the pixels in the sky

dtype_float: Any property

The inferred or specified data type for floating point arrays

Returns:

Type	Description
DTypeFloat	dtype of the floating point arrays

observed_pixels: npt.NDArray[np.integer] property

A 1-d array containing the original indices of the pixels that are fully valid for map-making

Returns:

Type	Description
NDArray[integer]	A 1-d array that contains all the pixel indices that are considered valid for map-making

pixel_flag: npt.NDArray[np.bool_] property

A 1-d boolean array of size npix where True indicates a bad pixel and False flags a valid pixel

Returns:

Type	Description
NDArray[bool_]	A 1-d boolean array of size npix where True indicates a dropped or pathological pixel

bad_pixels: npt.NDArray[np.integer] property

A 1-d array that contains all the pixel indices that will be excluded in map-making.

Returns:

Type	Description
NDArray[integer]	A 1-d array that contains all the pixel indices that will be excluded in map-making

old2new_pixel: npt.NDArray[np.integer] property

A 1-d array mapping old pixel indices to new pixel indices

Returns:

Type	Description
NDArray[integer]	A 1-d array mapping old pixel indices to new pixel indices

weighted_counts: npt.NDArray[np.number] property

A 1-d array accumulating the inverse noise weights per valid pixel

Returns:

Type	Description
NDArray[number]	A 1-d array accumulating the inverse noise weights per valid pixel

sin2phi: npt.NDArray[np.number] property

A 1-d array containing \(\sin(2\phi)\) evaluated at the valid time samples

Returns:

Type	Description
NDArray[number]	A 1-d array containing \(\sin(2\phi)\) evaluated at the valid time samples

cos2phi: npt.NDArray[np.number] property

A 1-d array containing \(\cos(2\phi)\) evaluated at the valid time samples

Returns:

Type	Description
NDArray[number]	A 1-d array containing \(\cos(2\phi)\) evaluated at the valid time samples

weighted_sin: npt.NDArray[np.number] property

A 1-d array accumulating the noise-weighted \(\sin(2\phi)\) sum per valid pixel

Returns:

Type	Description
NDArray[number]	A 1-d array accumulating the noise-weighted \(\sin(2\phi)\) sum per valid pixel

weighted_cos: npt.NDArray[np.number] property

A 1-d array accumulating the noise-weighted \(\cos(2\phi)\) sum per valid pixel

Returns:

Type	Description
NDArray[number]	A 1-d array accumulating the noise-weighted \(\cos(2\phi)\) sum per valid pixel

weighted_sin_sq: npt.NDArray[np.number] property

A 1-d array accumulating the noise-weighted \(\sin^2(2\phi)\) sum per valid pixel

Returns:

Type	Description
NDArray[number]	A 1-d array accumulating the noise-weighted \(\sin^2(2\phi)\) sum per valid pixel

weighted_cos_sq: npt.NDArray[np.number] property

A 1-d array accumulating the noise-weighted \(\cos^2(2\phi)\) sum per valid pixel

Returns:

Type	Description
NDArray[number]	A 1-d array accumulating the noise-weighted \(\cos^2(2\phi)\) sum per valid pixel

weighted_sincos: npt.NDArray[np.number] property

A 1-d array accumulating the noise-weighted \(\sin(2\phi)\cos(2\phi)\) sum per valid pixel

Returns:

Type	Description
NDArray[number]	A 1-d array accumulating the noise-weighted \(\sin(2\phi)\cos(2\phi)\) sum per valid pixel

one_over_determinant: npt.NDArray[np.number] property

A 1-d array containing the inverse determinant of the block-diagonal operator \(P^T diag(N)^{-1} P\)

Returns:

Type	Description
NDArray[number]	A 1-d array containing the inverse determinant of the block-diagonal operator \(P^T diag(N)^{-1} P\)

new_npix: int property

The number of pixels on which the map-making will be done

Returns:

Type	Description
int	Number of pixels on which the map-making will be done

nproc_reduce: int property

The size of each sub-communicator group within the node-level communicator

Returns:

Type	Description
int	The group size for local reductions

shared_mem_root: int property

The designated root rank within the node-level shared memory communicator

Returns:

Type	Description
int	The root rank

shared_mem_manager: SharedMemoryManager property

The manager class for MPI shared-memory communicators and windows

Returns:

Type	Description
SharedMemoryManager	The shared memory manager object.

obs_list: List[lbs.Observation] property

A list of the parsed litebird_sim observations.

Returns:

Type	Description
list[Observation]	The list of observations

nside: int property

The HEALPix resolution parameter.

Returns:

Type	Description
int	The \(N_{side}\) parameter

coordinate_system: lbs.CoordinateSystem property

The output celestial coordinate system used in data processing.

Returns:

Type	Description
CoordinateSystem	The configured coordinate system

Methods:

get_hit_counts() -> np.ma.MaskedArray

Returns hit counts of the pixel indices.

Returns:

Type	Description
NDArray[integer]	Hit counts of the pixel indices

Source code in brahmap/base/pts.py

def get_hit_counts(self) -> np.ma.MaskedArray:
    """Returns hit counts of the pixel indices.

    Returns
    -------
    npt.NDArray[np.integer]
        Hit counts of the pixel indices
    """
    hit_counts = np.ma.masked_array(
        data=np.zeros(self.npix),
        mask=np.logical_not(self._pixel_flag),
        fill_value=-1.6375e30,
    )

    hit_counts[~hit_counts.mask] = self._hit_counts
    return hit_counts

free_shmem_arrays() -> None

Frees all allocated shared-memory arrays and windows.

Returns:

Type	Description
None

Source code in brahmap/core/process_time_samples.py

def free_shmem_arrays(self) -> None:
    """Frees all allocated shared-memory arrays and windows.

    Returns
    -------
    None
    """
    MPI_UTILS.comm.barrier()
    if hasattr(self, "_SharedMemProcessTimeSamples__shared_mem_manager"):
        self.__shared_mem_manager.free_shared_arrays_all()