Data containers

Generating mock data

fakeit_for_multiple_parameters(obsconfs, model, parameters, rng_key=0, apply_stat=True, sparsify_matrix=False)

Convenience function to simulate multiple spectra from a given model and a set of parameters. This is supposed to be somewhat optimized and can handle multiple parameters at once without blowing up the memory. The parameters should be passed as a dictionary with the parameter name as the key and the parameter values as the values, the value can be a scalar or a nd-array.

Example:

from jaxspec.data.util import fakeit_for_multiple_parameters
from numpy.random import default_rng

rng = default_rng(42)
size = (10, 30)

parameters = {
    "tbabs_1_nh": rng.uniform(0.1, 0.4, size=size),
    "powerlaw_1_alpha": rng.uniform(1, 3, size=size),
    "powerlaw_1_norm": rng.exponential(10 ** (-0.5), size=size),
    "blackbodyrad_1_kT": rng.uniform(0.1, 3.0, size=size),
    "blackbodyrad_1_norm": rng.exponential(10 ** (-3), size=size)
}

spectra = fakeit_for_multiple_parameters(obsconf, model, parameters)

Parameters:

Name	Type	Description	Default
obsconfs	ObsConfiguration | list[ObsConfiguration]	The observational setup(s).	required
model	SpectralModel	The model to use.	required
parameters	Mapping[K, V]	The parameters of the model.	required
rng_key	int	The random number generator seed.	0
apply_stat	bool	Whether to apply Poisson statistic on the folded spectra or not.	True
sparsify_matrix	bool	Whether to sparsify the matrix or not.	False

Source code in src/jaxspec/data/util.py

def fakeit_for_multiple_parameters(
    obsconfs: ObsConfiguration | list[ObsConfiguration],
    model: SpectralModel,
    parameters: Mapping[K, V],
    rng_key: int = 0,
    apply_stat: bool = True,
    sparsify_matrix: bool = False,
):
    """
    Convenience function to simulate multiple spectra from a given model and a set of parameters.
    This is supposed to be somewhat optimized and can handle multiple parameters at once without blowing
    up the memory. The parameters should be passed as a dictionary with the parameter name as the key and
    the parameter values as the values, the value can be a scalar or a nd-array.

    # Example:

    ``` python
    from jaxspec.data.util import fakeit_for_multiple_parameters
    from numpy.random import default_rng

    rng = default_rng(42)
    size = (10, 30)

    parameters = {
        "tbabs_1_nh": rng.uniform(0.1, 0.4, size=size),
        "powerlaw_1_alpha": rng.uniform(1, 3, size=size),
        "powerlaw_1_norm": rng.exponential(10 ** (-0.5), size=size),
        "blackbodyrad_1_kT": rng.uniform(0.1, 3.0, size=size),
        "blackbodyrad_1_norm": rng.exponential(10 ** (-3), size=size)
    }

    spectra = fakeit_for_multiple_parameters(obsconf, model, parameters)
    ```

    Parameters:
        obsconfs: The observational setup(s).
        model: The model to use.
        parameters: The parameters of the model.
        rng_key: The random number generator seed.
        apply_stat: Whether to apply Poisson statistic on the folded spectra or not.
        sparsify_matrix: Whether to sparsify the matrix or not.
    """

    obsconf_list = [obsconfs] if isinstance(obsconfs, ObsConfiguration) else obsconfs
    fakeits = []

    for i, obsconf in enumerate(obsconf_list):
        countrate = forward_model_with_multiple_inputs(
            model, parameters, obsconf, sparse=sparsify_matrix
        )

        if apply_stat:
            with handlers.seed(rng_seed=rng_key):
                spectrum = numpyro.sample(
                    f"likelihood_obs_{i}",
                    numpyro.distributions.Poisson(countrate),
                )

        else:
            spectrum = countrate

        fakeits.append(spectrum)

    return fakeits[0] if len(fakeits) == 1 else fakeits

Data containers

ObsConfiguration

Bases: Dataset

Class to store the data of a folding model, which is the link between the unfolded and folded spectra.

Source code in src/jaxspec/data/obsconf.py

class ObsConfiguration(xr.Dataset):
    """
    Class to store the data of a folding model, which is the link between the unfolded and folded spectra.
    """

    transfer_matrix: xr.DataArray
    """The transfer matrix"""
    area: xr.DataArray
    """The effective area of the instrument"""
    exposure: xr.DataArray
    """The total exposure"""
    folded_counts: xr.DataArray
    """The observed counts, after grouping"""
    folded_background: xr.DataArray
    """The background counts, after grouping"""

    __slots__ = (
        "transfer_matrix",
        "area",
        "exposure",
        "folded_counts",
        "folded_background",
    )

    @property
    def in_energies(self):
        """
        The energy bounds of the unfolded bins in keV. The shape is (2, n_bins).
        """

        in_energies = np.stack(
            (
                np.asarray(self.coords["e_min_unfolded"], dtype=np.float64),
                np.asarray(self.coords["e_max_unfolded"], dtype=np.float64),
            )
        )

        return in_energies

    @property
    def out_energies(self):
        """
        The energy bounds of the folded bins in keV. The shape is (2, n_bins).
        """

        out_energies = np.stack(
            (
                np.asarray(self.coords["e_min_folded"].data, dtype=np.float64),
                np.asarray(self.coords["e_max_folded"].data, dtype=np.float64),
            )
        )

        return out_energies

    @classmethod
    def from_pha_file(
        cls,
        pha_path,
        rmf_path: str | None = None,
        arf_path: str | None = None,
        bkg_path: str | None = None,
        low_energy: float = 1e-20,
        high_energy: float = 1e20,
    ):
        r"""
        Build the observation configuration from a PHA file.

        Parameters:
            pha_path: The path to the PHA file.
            rmf_path: The path to the RMF file.
            arf_path: The path to the ARF file.
            bkg_path: The path to the background file.
            low_energy: The lower bound of the energy range to consider.
            high_energy: The upper bound of the energy range to consider.
        """

        from .util import data_path_finder

        arf_path_default, rmf_path_default, bkg_path_default = data_path_finder(pha_path)

        arf_path = arf_path_default if arf_path is None else arf_path
        rmf_path = rmf_path_default if rmf_path is None else rmf_path
        bkg_path = bkg_path_default if bkg_path is None else bkg_path

        instrument = Instrument.from_ogip_file(rmf_path, arf_path=arf_path)
        observation = Observation.from_pha_file(pha_path, bkg_path=bkg_path)

        return cls.from_instrument(
            instrument, observation, low_energy=low_energy, high_energy=high_energy
        )

    @classmethod
    def from_instrument(
        cls,
        instrument: Instrument,
        observation: Observation,
        low_energy: float = 1e-20,
        high_energy: float = 1e20,
    ):
        r"""
        Build the observation configuration from an [`Instrument`][jaxspec.data.Instrument] and an [`Observation`][jaxspec.data.Observation] object.

        Parameters:
            instrument: The instrument object.
            observation: The observation object.
            low_energy: The lower bound of the energy range to consider.
            high_energy: The upper bound of the energy range to consider.

        """
        # First we unpack all the xarray data to classical np array for efficiency
        # We also exclude the bins that are flagged with bad quality on the instrument
        quality_filter = observation.quality.data == 0
        grouping = (
            scipy.sparse.csr_array(observation.grouping.data.to_scipy_sparse()) * quality_filter
        )
        e_min_channel = instrument.coords["e_min_channel"].data
        e_max_channel = instrument.coords["e_max_channel"].data
        e_min_unfolded = instrument.coords["e_min_unfolded"].data
        e_max_unfolded = instrument.coords["e_max_unfolded"].data
        redistribution = scipy.sparse.csr_array(instrument.redistribution.data.to_scipy_sparse())
        area = instrument.area.data
        exposure = observation.exposure.data

        # Computing the lower and upper energies of the bins after grouping
        # This is just a trick to compute it without 10 lines of code
        grouping_nan = observation.grouping.data * quality_filter
        grouping_nan.fill_value = np.nan
        e_min = sparse.nanmin(grouping_nan * e_min_channel, axis=1).todense()
        e_max = sparse.nanmax(grouping_nan * e_max_channel, axis=1).todense()

        # Compute the transfer matrix
        transfer_matrix = grouping @ (redistribution * area * exposure)

        # Exclude bins out of the considered energy range, and bins without contribution from the RMF

        row_idx = (e_min > low_energy) & (e_max < high_energy) & (grouping.sum(axis=1) > 0)
        col_idx = (e_min_unfolded > 0) & (redistribution.sum(axis=0) > 0)

        # Apply this reduction to all the relevant arrays
        transfer_matrix = sparse.COO.from_scipy_sparse(transfer_matrix[row_idx][:, col_idx])
        folded_counts = observation.folded_counts.data[row_idx]
        folded_backratio = observation.folded_backratio.data[row_idx]
        area = instrument.area.data[col_idx]
        e_min_folded = e_min[row_idx]
        e_max_folded = e_max[row_idx]
        e_min_unfolded = e_min_unfolded[col_idx]
        e_max_unfolded = e_max_unfolded[col_idx]

        if observation.folded_background is not None:
            folded_background = observation.folded_background.data[row_idx]
            folded_background_unscaled = observation.folded_background_unscaled.data[row_idx]
        else:
            folded_background = np.zeros_like(folded_counts)
            folded_background_unscaled = np.zeros_like(folded_counts)

        data_dict = {
            "transfer_matrix": (
                ["folded_channel", "unfolded_channel"],
                transfer_matrix,
                {
                    "description": "Transfer matrix to use to fold the incoming spectrum. It is built and restricted using the grouping, redistribution matrix, effective area, quality flags and energy bands defined by the user."
                },
            ),
            "area": (
                ["unfolded_channel"],
                area,
                {
                    "description": "Effective area with the same restrictions as the transfer matrix.",
                    "units": "cm^2",
                },
            ),
            "exposure": ([], exposure, {"description": "Total exposure", "unit": "s"}),
            "folded_counts": (
                ["folded_channel"],
                folded_counts,
                {
                    "description": "Folded counts after grouping, with the same restrictions as the transfer matrix.",
                    "unit": "photons",
                },
            ),
            "folded_backratio": (
                ["folded_channel"],
                folded_backratio,
                {
                    "description": "Background scaling after grouping, with the same restrictions as the transfer matrix."
                },
            ),
            "folded_background": (
                ["folded_channel"],
                folded_background,
                {
                    "description": "Folded background counts after grouping, with the same restrictions as the transfer matrix.",
                    "unit": "photons",
                },
            ),
            "folded_background_unscaled": (
                ["folded_channel"],
                folded_background_unscaled,
                {
                    "description": "To be done",
                    "unit": "photons",
                },
            ),
        }

        return cls(
            data_dict,
            coords={
                "e_min_folded": (
                    ["folded_channel"],
                    e_min_folded,
                    {"description": "Low energy of folded channel"},
                ),
                "e_max_folded": (
                    ["folded_channel"],
                    e_max_folded,
                    {"description": "High energy of folded channel"},
                ),
                "e_min_unfolded": (
                    ["unfolded_channel"],
                    e_min_unfolded,
                    {"description": "Low energy of unfolded channel"},
                ),
                "e_max_unfolded": (
                    ["unfolded_channel"],
                    e_max_unfolded,
                    {"description": "High energy of unfolded channel"},
                ),
            },
            attrs=observation.attrs | instrument.attrs,
        )

    @classmethod
    def mock_from_instrument(
        cls,
        instrument: Instrument,
        exposure: float,
        low_energy: float = 1e-300,
        high_energy: float = 1e300,
    ):
        """
        Create a mock observation configuration from an instrument object. The fake observation will have zero counts.

        Parameters:
            instrument: The instrument object.
            exposure: The total exposure of the mock observation.
            low_energy: The lower bound of the energy range to consider.
            high_energy: The upper bound of the energy range to consider.
        """

        n_channels = len(instrument.coords["instrument_channel"])

        observation = Observation.from_matrix(
            np.zeros(n_channels),
            sparse.eye(n_channels),
            np.arange(n_channels),
            np.zeros(n_channels, dtype=bool),
            exposure,
            backratio=np.ones(n_channels),
            attributes={"description": "Mock observation"} | instrument.attrs,
        )

        return cls.from_instrument(
            instrument, observation, low_energy=low_energy, high_energy=high_energy
        )

    def plot_counts(self, **kwargs):
        return self.folded_counts.plot.step(x="e_min_folded", where="post", **kwargs)

area instance-attribute

The effective area of the instrument

exposure instance-attribute

The total exposure

folded_background instance-attribute

The background counts, after grouping

folded_counts instance-attribute

The observed counts, after grouping

in_energies property

The energy bounds of the unfolded bins in keV. The shape is (2, n_bins).

out_energies property

The energy bounds of the folded bins in keV. The shape is (2, n_bins).

transfer_matrix instance-attribute

The transfer matrix

from_instrument(instrument, observation, low_energy=1e-20, high_energy=1e+20) classmethod

Build the observation configuration from an Instrument and an Observation object.

Parameters:

Name	Type	Description	Default
instrument	Instrument	The instrument object.	required
observation	Observation	The observation object.	required
low_energy	float	The lower bound of the energy range to consider.	1e-20
high_energy	float	The upper bound of the energy range to consider.	1e+20

Source code in src/jaxspec/data/obsconf.py

@classmethod
def from_instrument(
    cls,
    instrument: Instrument,
    observation: Observation,
    low_energy: float = 1e-20,
    high_energy: float = 1e20,
):
    r"""
    Build the observation configuration from an [`Instrument`][jaxspec.data.Instrument] and an [`Observation`][jaxspec.data.Observation] object.

    Parameters:
        instrument: The instrument object.
        observation: The observation object.
        low_energy: The lower bound of the energy range to consider.
        high_energy: The upper bound of the energy range to consider.

    """
    # First we unpack all the xarray data to classical np array for efficiency
    # We also exclude the bins that are flagged with bad quality on the instrument
    quality_filter = observation.quality.data == 0
    grouping = (
        scipy.sparse.csr_array(observation.grouping.data.to_scipy_sparse()) * quality_filter
    )
    e_min_channel = instrument.coords["e_min_channel"].data
    e_max_channel = instrument.coords["e_max_channel"].data
    e_min_unfolded = instrument.coords["e_min_unfolded"].data
    e_max_unfolded = instrument.coords["e_max_unfolded"].data
    redistribution = scipy.sparse.csr_array(instrument.redistribution.data.to_scipy_sparse())
    area = instrument.area.data
    exposure = observation.exposure.data

    # Computing the lower and upper energies of the bins after grouping
    # This is just a trick to compute it without 10 lines of code
    grouping_nan = observation.grouping.data * quality_filter
    grouping_nan.fill_value = np.nan
    e_min = sparse.nanmin(grouping_nan * e_min_channel, axis=1).todense()
    e_max = sparse.nanmax(grouping_nan * e_max_channel, axis=1).todense()

    # Compute the transfer matrix
    transfer_matrix = grouping @ (redistribution * area * exposure)

    # Exclude bins out of the considered energy range, and bins without contribution from the RMF

    row_idx = (e_min > low_energy) & (e_max < high_energy) & (grouping.sum(axis=1) > 0)
    col_idx = (e_min_unfolded > 0) & (redistribution.sum(axis=0) > 0)

    # Apply this reduction to all the relevant arrays
    transfer_matrix = sparse.COO.from_scipy_sparse(transfer_matrix[row_idx][:, col_idx])
    folded_counts = observation.folded_counts.data[row_idx]
    folded_backratio = observation.folded_backratio.data[row_idx]
    area = instrument.area.data[col_idx]
    e_min_folded = e_min[row_idx]
    e_max_folded = e_max[row_idx]
    e_min_unfolded = e_min_unfolded[col_idx]
    e_max_unfolded = e_max_unfolded[col_idx]

    if observation.folded_background is not None:
        folded_background = observation.folded_background.data[row_idx]
        folded_background_unscaled = observation.folded_background_unscaled.data[row_idx]
    else:
        folded_background = np.zeros_like(folded_counts)
        folded_background_unscaled = np.zeros_like(folded_counts)

    data_dict = {
        "transfer_matrix": (
            ["folded_channel", "unfolded_channel"],
            transfer_matrix,
            {
                "description": "Transfer matrix to use to fold the incoming spectrum. It is built and restricted using the grouping, redistribution matrix, effective area, quality flags and energy bands defined by the user."
            },
        ),
        "area": (
            ["unfolded_channel"],
            area,
            {
                "description": "Effective area with the same restrictions as the transfer matrix.",
                "units": "cm^2",
            },
        ),
        "exposure": ([], exposure, {"description": "Total exposure", "unit": "s"}),
        "folded_counts": (
            ["folded_channel"],
            folded_counts,
            {
                "description": "Folded counts after grouping, with the same restrictions as the transfer matrix.",
                "unit": "photons",
            },
        ),
        "folded_backratio": (
            ["folded_channel"],
            folded_backratio,
            {
                "description": "Background scaling after grouping, with the same restrictions as the transfer matrix."
            },
        ),
        "folded_background": (
            ["folded_channel"],
            folded_background,
            {
                "description": "Folded background counts after grouping, with the same restrictions as the transfer matrix.",
                "unit": "photons",
            },
        ),
        "folded_background_unscaled": (
            ["folded_channel"],
            folded_background_unscaled,
            {
                "description": "To be done",
                "unit": "photons",
            },
        ),
    }

    return cls(
        data_dict,
        coords={
            "e_min_folded": (
                ["folded_channel"],
                e_min_folded,
                {"description": "Low energy of folded channel"},
            ),
            "e_max_folded": (
                ["folded_channel"],
                e_max_folded,
                {"description": "High energy of folded channel"},
            ),
            "e_min_unfolded": (
                ["unfolded_channel"],
                e_min_unfolded,
                {"description": "Low energy of unfolded channel"},
            ),
            "e_max_unfolded": (
                ["unfolded_channel"],
                e_max_unfolded,
                {"description": "High energy of unfolded channel"},
            ),
        },
        attrs=observation.attrs | instrument.attrs,
    )

from_pha_file(pha_path, rmf_path=None, arf_path=None, bkg_path=None, low_energy=1e-20, high_energy=1e+20) classmethod

Build the observation configuration from a PHA file.

Parameters:

Name	Type	Description	Default
pha_path		The path to the PHA file.	required
rmf_path	str | None	The path to the RMF file.	None
arf_path	str | None	The path to the ARF file.	None
bkg_path	str | None	The path to the background file.	None
low_energy	float	The lower bound of the energy range to consider.	1e-20
high_energy	float	The upper bound of the energy range to consider.	1e+20

Source code in src/jaxspec/data/obsconf.py

@classmethod
def from_pha_file(
    cls,
    pha_path,
    rmf_path: str | None = None,
    arf_path: str | None = None,
    bkg_path: str | None = None,
    low_energy: float = 1e-20,
    high_energy: float = 1e20,
):
    r"""
    Build the observation configuration from a PHA file.

    Parameters:
        pha_path: The path to the PHA file.
        rmf_path: The path to the RMF file.
        arf_path: The path to the ARF file.
        bkg_path: The path to the background file.
        low_energy: The lower bound of the energy range to consider.
        high_energy: The upper bound of the energy range to consider.
    """

    from .util import data_path_finder

    arf_path_default, rmf_path_default, bkg_path_default = data_path_finder(pha_path)

    arf_path = arf_path_default if arf_path is None else arf_path
    rmf_path = rmf_path_default if rmf_path is None else rmf_path
    bkg_path = bkg_path_default if bkg_path is None else bkg_path

    instrument = Instrument.from_ogip_file(rmf_path, arf_path=arf_path)
    observation = Observation.from_pha_file(pha_path, bkg_path=bkg_path)

    return cls.from_instrument(
        instrument, observation, low_energy=low_energy, high_energy=high_energy
    )

mock_from_instrument(instrument, exposure, low_energy=1e-300, high_energy=1e+300) classmethod

Create a mock observation configuration from an instrument object. The fake observation will have zero counts.

Parameters:

Name	Type	Description	Default
instrument	Instrument	The instrument object.	required
exposure	float	The total exposure of the mock observation.	required
low_energy	float	The lower bound of the energy range to consider.	1e-300
high_energy	float	The upper bound of the energy range to consider.	1e+300

Source code in src/jaxspec/data/obsconf.py

@classmethod
def mock_from_instrument(
    cls,
    instrument: Instrument,
    exposure: float,
    low_energy: float = 1e-300,
    high_energy: float = 1e300,
):
    """
    Create a mock observation configuration from an instrument object. The fake observation will have zero counts.

    Parameters:
        instrument: The instrument object.
        exposure: The total exposure of the mock observation.
        low_energy: The lower bound of the energy range to consider.
        high_energy: The upper bound of the energy range to consider.
    """

    n_channels = len(instrument.coords["instrument_channel"])

    observation = Observation.from_matrix(
        np.zeros(n_channels),
        sparse.eye(n_channels),
        np.arange(n_channels),
        np.zeros(n_channels, dtype=bool),
        exposure,
        backratio=np.ones(n_channels),
        attributes={"description": "Mock observation"} | instrument.attrs,
    )

    return cls.from_instrument(
        instrument, observation, low_energy=low_energy, high_energy=high_energy
    )

Instrument

Bases: Dataset

Class to store the data of an instrument

Source code in src/jaxspec/data/instrument.py

class Instrument(xr.Dataset):
    """
    Class to store the data of an instrument
    """

    redistribution: xr.DataArray
    """The photon redistribution probability matrix"""
    area: xr.DataArray
    """The effective area of the instrument"""

    __slots__ = (
        "redistribution",
        "area",
        "e_min_out",
        "e_max_out",
        "e_min_in",
        "e_max_in",
    )

    @classmethod
    def from_matrix(
        cls,
        redistribution_matrix,
        spectral_response,
        e_min_unfolded,
        e_max_unfolded,
        e_min_channel,
        e_max_channel,
    ):
        return cls(
            {
                "redistribution": (
                    ["instrument_channel", "unfolded_channel"],
                    redistribution_matrix,
                    {"description": "Redistribution matrix"},
                ),
                "area": (
                    ["unfolded_channel"],
                    np.array(spectral_response, dtype=np.float64),
                    {"description": "Effective area", "units": "cm^2"},
                ),
            },
            coords={
                "e_min_unfolded": (
                    ["unfolded_channel"],
                    np.array(e_min_unfolded, dtype=np.float64),
                    {"description": "Low bin energy for ingoing channels", "units": "keV"},
                ),
                "e_max_unfolded": (
                    ["unfolded_channel"],
                    np.array(e_max_unfolded, dtype=np.float64),
                    {"description": "High bin energy for ingoing channels", "units": "keV"},
                ),
                "e_min_channel": (
                    ["instrument_channel"],
                    np.array(e_min_channel, dtype=np.float64),
                    {"description": "Low bin energy for outgoing channels", "units": "keV"},
                ),
                "e_max_channel": (
                    ["instrument_channel"],
                    np.array(e_max_channel, dtype=np.float64),
                    {"description": "High bin energy for outgoing channels", "units": "keV"},
                ),
            },
            attrs={"description": "X-ray instrument response dataset"},
        )

    @classmethod
    def from_ogip_file(cls, rmf_path: str | os.PathLike, arf_path: str | os.PathLike | None = None):
        """
        Load the data from OGIP files.

        Parameters:
            rmf_path: The RMF file path.
            arf_path: The ARF file path.
        """

        rmf = DataRMF.from_file(rmf_path)

        if arf_path is not None:
            specresp = DataARF.from_file(arf_path).specresp

        else:
            specresp = rmf.matrix.sum(axis=0)
            rmf.sparse_matrix /= specresp

        return cls.from_matrix(
            rmf.sparse_matrix, specresp, rmf.energ_lo, rmf.energ_hi, rmf.e_min, rmf.e_max
        )

    def plot_redistribution(
        self,
        xscale: str = "log",
        yscale: str = "log",
        cmap=None,
        vmin: float = 1e-6,
        vmax: float = 1e0,
        add_labels: bool = True,
        **kwargs,
    ):
        """
        Plot the redistribution probability matrix

        Parameters:
            xscale : The scale of the x-axis.
            yscale : The scale of the y-axis.
            cmap : The colormap to use.
            vmin : The minimum value for the colormap.
            vmax : The maximum value for the colormap.
            add_labels : Whether to add labels to the plot.
            **kwargs : `kwargs` passed to https://docs.xarray.dev/en/latest/generated/xarray.plot.pcolormesh.html#xarray.plot.pcolormesh
        """

        import cmasher as cmr

        return xr.plot.pcolormesh(
            self.redistribution,
            x="e_max_unfolded",
            y="e_max_channel",
            xscale=xscale,
            yscale=yscale,
            cmap=cmr.ember_r if cmap is None else cmap,
            norm=colors.LogNorm(vmin=vmin, vmax=vmax),
            add_labels=add_labels,
            **kwargs,
        )

    def plot_area(self, xscale: str = "log", yscale: str = "log", where: str = "post", **kwargs):
        """
        Plot the effective area

        Parameters:
            xscale : The scale of the x-axis.
            yscale : The scale of the y-axis.
            where : The position of the steps.
            **kwargs : `kwargs` passed to https://docs.xarray.dev/en/latest/generated/xarray.DataArray.plot.line.html#xarray.DataArray.plot.line
        """

        return self.area.plot.step(
            x="e_min_unfolded", xscale=xscale, yscale=yscale, where=where, **kwargs
        )

area instance-attribute

The effective area of the instrument

redistribution instance-attribute

The photon redistribution probability matrix

from_ogip_file(rmf_path, arf_path=None) classmethod

Load the data from OGIP files.

Parameters:

Name	Type	Description	Default
rmf_path	str | PathLike	The RMF file path.	required
arf_path	str | PathLike | None	The ARF file path.	None

Source code in src/jaxspec/data/instrument.py

@classmethod
def from_ogip_file(cls, rmf_path: str | os.PathLike, arf_path: str | os.PathLike | None = None):
    """
    Load the data from OGIP files.

    Parameters:
        rmf_path: The RMF file path.
        arf_path: The ARF file path.
    """

    rmf = DataRMF.from_file(rmf_path)

    if arf_path is not None:
        specresp = DataARF.from_file(arf_path).specresp

    else:
        specresp = rmf.matrix.sum(axis=0)
        rmf.sparse_matrix /= specresp

    return cls.from_matrix(
        rmf.sparse_matrix, specresp, rmf.energ_lo, rmf.energ_hi, rmf.e_min, rmf.e_max
    )

plot_area(xscale='log', yscale='log', where='post', **kwargs)

Plot the effective area

Parameters:

Name	Type	Description	Default
xscale		The scale of the x-axis.	'log'
yscale		The scale of the y-axis.	'log'
where		The position of the steps.	'post'
**kwargs		kwargs passed to https://docs.xarray.dev/en/latest/generated/xarray.DataArray.plot.line.html#xarray.DataArray.plot.line	{}

Source code in src/jaxspec/data/instrument.py

def plot_area(self, xscale: str = "log", yscale: str = "log", where: str = "post", **kwargs):
    """
    Plot the effective area

    Parameters:
        xscale : The scale of the x-axis.
        yscale : The scale of the y-axis.
        where : The position of the steps.
        **kwargs : `kwargs` passed to https://docs.xarray.dev/en/latest/generated/xarray.DataArray.plot.line.html#xarray.DataArray.plot.line
    """

    return self.area.plot.step(
        x="e_min_unfolded", xscale=xscale, yscale=yscale, where=where, **kwargs
    )

plot_redistribution(xscale='log', yscale='log', cmap=None, vmin=1e-06, vmax=1.0, add_labels=True, **kwargs)

Plot the redistribution probability matrix

Parameters:

Name	Type	Description	Default
xscale		The scale of the x-axis.	'log'
yscale		The scale of the y-axis.	'log'
cmap		The colormap to use.	None
vmin		The minimum value for the colormap.	1e-06
vmax		The maximum value for the colormap.	1.0
add_labels		Whether to add labels to the plot.	True
**kwargs		kwargs passed to https://docs.xarray.dev/en/latest/generated/xarray.plot.pcolormesh.html#xarray.plot.pcolormesh	{}

Source code in src/jaxspec/data/instrument.py

def plot_redistribution(
    self,
    xscale: str = "log",
    yscale: str = "log",
    cmap=None,
    vmin: float = 1e-6,
    vmax: float = 1e0,
    add_labels: bool = True,
    **kwargs,
):
    """
    Plot the redistribution probability matrix

    Parameters:
        xscale : The scale of the x-axis.
        yscale : The scale of the y-axis.
        cmap : The colormap to use.
        vmin : The minimum value for the colormap.
        vmax : The maximum value for the colormap.
        add_labels : Whether to add labels to the plot.
        **kwargs : `kwargs` passed to https://docs.xarray.dev/en/latest/generated/xarray.plot.pcolormesh.html#xarray.plot.pcolormesh
    """

    import cmasher as cmr

    return xr.plot.pcolormesh(
        self.redistribution,
        x="e_max_unfolded",
        y="e_max_channel",
        xscale=xscale,
        yscale=yscale,
        cmap=cmr.ember_r if cmap is None else cmap,
        norm=colors.LogNorm(vmin=vmin, vmax=vmax),
        add_labels=add_labels,
        **kwargs,
    )

Observation

Bases: Dataset

Class to store the data of an observation

Source code in src/jaxspec/data/observation.py

class Observation(xr.Dataset):
    """
    Class to store the data of an observation
    """

    counts: xr.DataArray
    """The observed counts"""
    folded_counts: xr.DataArray
    """The observed counts, after grouping"""
    grouping: xr.DataArray
    """The grouping matrix"""
    quality: xr.DataArray
    """The quality flag"""
    exposure: xr.DataArray
    """The total exposure"""
    background: xr.DataArray
    """The background counts if provided, otherwise 0"""
    folded_background: xr.DataArray
    """The background counts, after grouping"""

    __slots__ = (
        "grouping",
        "channel",
        "quality",
        "exposure",
        "background",
        "folded_background",
        "counts",
        "folded_counts",
    )

    _default_attributes = {"description": "X-ray observation dataset"}

    @classmethod
    def from_matrix(
        cls,
        counts,
        grouping,
        channel,
        quality,
        exposure,
        background=None,
        background_unscaled=None,
        backratio=1.0,
        attributes: dict | None = None,
    ):
        if attributes is None:
            attributes = {}

        if background is None or background_unscaled is None:
            background = np.zeros_like(counts, dtype=np.int64)
            background_unscaled = np.zeros_like(counts, dtype=np.int64)

        data_dict = {
            "counts": (
                ["instrument_channel"],
                np.asarray(counts, dtype=np.int64),
                {"description": "Counts", "unit": "photons"},
            ),
            "folded_counts": (
                ["folded_channel"],
                np.asarray(np.ma.filled(grouping @ counts), dtype=np.int64),
                {"description": "Folded counts, after grouping", "unit": "photons"},
            ),
            "grouping": (
                ["folded_channel", "instrument_channel"],
                grouping,
                {"description": "Grouping matrix."},
            ),
            "quality": (
                ["instrument_channel"],
                np.asarray(quality, dtype=np.int64),
                {"description": "Quality flag."},
            ),
            "exposure": ([], float(exposure), {"description": "Total exposure", "unit": "s"}),
            "backratio": (
                ["instrument_channel"],
                np.asarray(backratio, dtype=float),
                {"description": "Background scaling (SRC_BACKSCAL/BKG_BACKSCAL)"},
            ),
            "folded_backratio": (
                ["folded_channel"],
                np.asarray(np.ma.filled(grouping @ backratio), dtype=float),
                {"description": "Background scaling after grouping"},
            ),
            "background": (
                ["instrument_channel"],
                np.asarray(background, dtype=np.int64),
                {"description": "Background counts", "unit": "photons"},
            ),
            "folded_background_unscaled": (
                ["folded_channel"],
                np.asarray(np.ma.filled(grouping @ background_unscaled), dtype=np.int64),
                {"description": "Background counts", "unit": "photons"},
            ),
            "folded_background": (
                ["folded_channel"],
                np.asarray(np.ma.filled(grouping @ background), dtype=np.float64),
                {"description": "Background counts", "unit": "photons"},
            ),
        }

        return cls(
            data_dict,
            coords={
                "channel": (
                    ["instrument_channel"],
                    np.asarray(channel, dtype=np.int64),
                    {"description": "Channel number"},
                ),
                "grouped_channel": (
                    ["folded_channel"],
                    np.arange(len(grouping @ counts), dtype=np.int64),
                    {"description": "Channel number"},
                ),
            },
            attrs=cls._default_attributes
            if attributes is None
            else attributes | cls._default_attributes,
        )

    @classmethod
    def from_ogip_container(cls, pha: DataPHA, bkg: DataPHA | None = None, **metadata):
        if bkg is not None:
            backratio = np.nan_to_num(
                (pha.backscal * pha.exposure * pha.areascal)
                / (bkg.backscal * bkg.exposure * bkg.areascal)
            )
        else:
            backratio = np.ones_like(pha.counts)

        if (bkg is not None) and ("NET" in pha.flags):
            counts = pha.counts + bkg.counts * backratio
        else:
            counts = pha.counts

        return cls.from_matrix(
            counts,
            pha.grouping,
            pha.channel,
            pha.quality,
            pha.exposure,
            backratio=backratio,
            background=bkg.counts * backratio if bkg is not None else None,
            background_unscaled=bkg.counts if bkg is not None else None,
            attributes=metadata,
        )

    @classmethod
    def from_pha_file(cls, pha_path: str, bkg_path: str | None = None, **metadata):
        """
        Build an observation from a PHA file

        Parameters:
            pha_path : Path to the PHA file
            bkg_path : Path to the background file
            metadata : Additional metadata to add to the observation
        """
        from .util import data_path_finder

        arf_path, rmf_path, bkg_path_default = data_path_finder(pha_path)
        bkg_path = bkg_path_default if bkg_path is None else bkg_path

        pha = DataPHA.from_file(pha_path)
        bkg = DataPHA.from_file(bkg_path) if bkg_path is not None else None

        if metadata is None:
            metadata = {}

        metadata.update(
            observation_file=pha_path,
            background_file=bkg_path,
            response_matrix_file=rmf_path,
            ancillary_response_file=arf_path,
        )

        return cls.from_ogip_container(pha, bkg=bkg, **metadata)

    def plot_counts(self, **kwargs):
        """
        Plot the counts

        Parameters:
            **kwargs : `kwargs` passed to https://docs.xarray.dev/en/latest/generated/xarray.DataArray.plot.step.html#xarray.DataArray.plot.line
        """

        return self.counts.plot.step(x="instrument_channel", yscale="log", where="post", **kwargs)

    def plot_grouping(self):
        """
        Plot the grouping matrix and compare the grouped counts to the true counts
        in the original channels.
        """

        import matplotlib.pyplot as plt
        import seaborn as sns

        fig = plt.figure(figsize=(6, 6))
        gs = fig.add_gridspec(
            2,
            2,
            width_ratios=(4, 1),
            height_ratios=(1, 4),
            left=0.1,
            right=0.9,
            bottom=0.1,
            top=0.9,
            wspace=0.05,
            hspace=0.05,
        )
        ax = fig.add_subplot(gs[1, 0])
        ax_histx = fig.add_subplot(gs[0, 0], sharex=ax)
        ax_histy = fig.add_subplot(gs[1, 1], sharey=ax)
        sns.heatmap(self.grouping.data.todense().T, ax=ax, cbar=False)
        ax_histx.step(np.arange(len(self.folded_counts)), self.folded_counts, where="post")
        ax_histy.step(self.counts, np.arange(len(self.counts)), where="post")

        ax.set_xlabel("Grouped channels")
        ax.set_ylabel("Channels")
        ax_histx.set_ylabel("Grouped counts")
        ax_histy.set_xlabel("Counts")

        ax_histx.semilogy()
        ax_histy.semilogx()

        _ = [label.set_visible(False) for label in ax_histx.get_xticklabels()]
        _ = [label.set_visible(False) for label in ax_histy.get_yticklabels()]

background instance-attribute

The background counts if provided, otherwise 0

counts instance-attribute

The observed counts

exposure instance-attribute

The total exposure

folded_background instance-attribute

The background counts, after grouping

folded_counts instance-attribute

The observed counts, after grouping

grouping instance-attribute

The grouping matrix

quality instance-attribute

The quality flag

from_pha_file(pha_path, bkg_path=None, **metadata) classmethod

Build an observation from a PHA file

Parameters:

Name	Type	Description	Default
pha_path		Path to the PHA file	required
bkg_path		Path to the background file	None
metadata		Additional metadata to add to the observation	{}

Source code in src/jaxspec/data/observation.py

@classmethod
def from_pha_file(cls, pha_path: str, bkg_path: str | None = None, **metadata):
    """
    Build an observation from a PHA file

    Parameters:
        pha_path : Path to the PHA file
        bkg_path : Path to the background file
        metadata : Additional metadata to add to the observation
    """
    from .util import data_path_finder

    arf_path, rmf_path, bkg_path_default = data_path_finder(pha_path)
    bkg_path = bkg_path_default if bkg_path is None else bkg_path

    pha = DataPHA.from_file(pha_path)
    bkg = DataPHA.from_file(bkg_path) if bkg_path is not None else None

    if metadata is None:
        metadata = {}

    metadata.update(
        observation_file=pha_path,
        background_file=bkg_path,
        response_matrix_file=rmf_path,
        ancillary_response_file=arf_path,
    )

    return cls.from_ogip_container(pha, bkg=bkg, **metadata)

plot_counts(**kwargs)

Plot the counts

Parameters:

Name	Type	Description	Default
**kwargs		kwargs passed to https://docs.xarray.dev/en/latest/generated/xarray.DataArray.plot.step.html#xarray.DataArray.plot.line	{}

Source code in src/jaxspec/data/observation.py

def plot_counts(self, **kwargs):
    """
    Plot the counts

    Parameters:
        **kwargs : `kwargs` passed to https://docs.xarray.dev/en/latest/generated/xarray.DataArray.plot.step.html#xarray.DataArray.plot.line
    """

    return self.counts.plot.step(x="instrument_channel", yscale="log", where="post", **kwargs)

plot_grouping()

Plot the grouping matrix and compare the grouped counts to the true counts in the original channels.

Source code in src/jaxspec/data/observation.py

def plot_grouping(self):
    """
    Plot the grouping matrix and compare the grouped counts to the true counts
    in the original channels.
    """

    import matplotlib.pyplot as plt
    import seaborn as sns

    fig = plt.figure(figsize=(6, 6))
    gs = fig.add_gridspec(
        2,
        2,
        width_ratios=(4, 1),
        height_ratios=(1, 4),
        left=0.1,
        right=0.9,
        bottom=0.1,
        top=0.9,
        wspace=0.05,
        hspace=0.05,
    )
    ax = fig.add_subplot(gs[1, 0])
    ax_histx = fig.add_subplot(gs[0, 0], sharex=ax)
    ax_histy = fig.add_subplot(gs[1, 1], sharey=ax)
    sns.heatmap(self.grouping.data.todense().T, ax=ax, cbar=False)
    ax_histx.step(np.arange(len(self.folded_counts)), self.folded_counts, where="post")
    ax_histy.step(self.counts, np.arange(len(self.counts)), where="post")

    ax.set_xlabel("Grouped channels")
    ax.set_ylabel("Channels")
    ax_histx.set_ylabel("Grouped counts")
    ax_histy.set_xlabel("Counts")

    ax_histx.semilogy()
    ax_histy.semilogx()

    _ = [label.set_visible(False) for label in ax_histx.get_xticklabels()]
    _ = [label.set_visible(False) for label in ax_histy.get_yticklabels()]

OGIP data parsers

DataARF

Class to handle ARF data defined with OGIP standards.

References

• The Calibration Requirements for Spectral Analysis (Definition of RMF and ARF file formats)
• The Calibration Requirements for Spectral Analysis Addendum: Changes log

Source code in src/jaxspec/data/ogip.py

class DataARF:
    r"""
    Class to handle ARF data defined with OGIP standards.

    ??? info "References"
        * [The Calibration Requirements for Spectral Analysis (Definition of RMF and ARF file formats)](https://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/docs/memos/cal_gen_92_002/cal_gen_92_002.html)
        * [The Calibration Requirements for Spectral Analysis Addendum: Changes log](https://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/docs/memos/cal_gen_92_002a/cal_gen_92_002a.html)
    """

    def __init__(self, energ_lo, energ_hi, specresp):
        self.specresp = specresp
        self.energ_lo = energ_lo
        self.energ_hi = energ_hi

    @classmethod
    def from_file(cls, arf_file: str | os.PathLike):
        """
        Load the data from an ARF file.

        Parameters:
            arf_file: The ARF file path.
        """

        arf_table = QTable.read(arf_file)

        return cls(
            arf_table["ENERG_LO"],
            arf_table["ENERG_HI"],
            arf_table["SPECRESP"].to(u.cm**2).value,
        )

from_file(arf_file) classmethod

Load the data from an ARF file.

Parameters:

Name	Type	Description	Default
arf_file	str | PathLike	The ARF file path.	required

Source code in src/jaxspec/data/ogip.py

@classmethod
def from_file(cls, arf_file: str | os.PathLike):
    """
    Load the data from an ARF file.

    Parameters:
        arf_file: The ARF file path.
    """

    arf_table = QTable.read(arf_file)

    return cls(
        arf_table["ENERG_LO"],
        arf_table["ENERG_HI"],
        arf_table["SPECRESP"].to(u.cm**2).value,
    )

DataPHA

Class to handle PHA data defined with OGIP standards.

References

• The OGIP standard PHA file format

Source code in src/jaxspec/data/ogip.py

class DataPHA:
    r"""
    Class to handle PHA data defined with OGIP standards.
    ??? info "References"
        * [The OGIP standard PHA file format](https://heasarc.gsfc.nasa.gov/docs/heasarc/ofwg/docs/spectra/ogip_92_007/node5.html)
    """

    def __init__(
        self,
        channel,
        counts,
        exposure,
        grouping=None,
        quality=None,
        backfile=None,
        respfile=None,
        ancrfile=None,
        backscal=1.0,
        areascal=1.0,
        flags=None,
    ):
        self.channel = np.asarray(channel, dtype=int)
        self.counts = np.asarray(counts, dtype=int)
        self.exposure = float(exposure)

        self.quality = np.asarray(quality, dtype=int)
        self.backfile = backfile
        self.respfile = respfile
        self.ancrfile = ancrfile
        self.backscal = np.asarray(backscal, dtype=float)
        self.areascal = np.asarray(areascal, dtype=float)
        self.flags = flags

        if grouping is not None:
            # Indices array of the beginning of each group
            b_grp = np.where(grouping == 1)[0]
            # Indices array of the ending of each group
            e_grp = np.hstack((b_grp[1:], len(channel)))

            # Prepare data for sparse matrix
            rows = []
            cols = []
            data = []

            for i in range(len(b_grp)):
                for j in range(b_grp[i], e_grp[i]):
                    rows.append(i)
                    cols.append(j)
                    data.append(True)

            # Create a COO sparse matrix
            grp_matrix = sparse.COO(
                (data, (rows, cols)), shape=(len(b_grp), len(channel)), fill_value=0
            )

        else:
            # Identity matrix case, use sparse for efficiency
            grp_matrix = sparse.eye(len(channel), format="coo", dtype=bool)

        self.grouping = grp_matrix

    @classmethod
    def from_file(cls, pha_file: str | os.PathLike):
        """
        Load the data from a PHA file.

        Parameters:
            pha_file: The PHA file path.
        """

        data = QTable.read(pha_file, "SPECTRUM")
        header = fits.getheader(pha_file, "SPECTRUM")
        flags = []

        if header.get("HDUCLAS3") == "RATE":
            raise ValueError(
                f"The HDUCLAS3={header.get('HDUCLAS3')} keyword in the PHA file is not supported."
                f"Please open an issue if this is required."
            )

        if header.get("HDUCLAS4") == "TYPE:II":
            raise ValueError(
                f"The HDUCLAS4={header.get('HDUCLAS4')} keyword in the PHA file is not supported."
                f"Please open an issue if this is required."
            )

        if header.get("GROUPING") == 0:
            grouping = None
        elif "GROUPING" in data.colnames:
            grouping = data["GROUPING"]
        else:
            raise ValueError("No grouping column found in the PHA file.")

        if header.get("QUALITY") == 0:
            quality = np.zeros(len(data["CHANNEL"]), dtype=bool)
        elif "QUALITY" in data.colnames:
            quality = data["QUALITY"]
        else:
            raise ValueError("No QUALITY column found in the PHA file.")

        if "BACKSCAL" in header:
            backscal = header["BACKSCAL"] * np.ones_like(data["CHANNEL"])
        elif "BACKSCAL" in data.colnames:
            backscal = data["BACKSCAL"]
        else:
            raise ValueError("No BACKSCAL found in the PHA file.")

        backscal = np.where(backscal == 0, 1.0, backscal)

        if "AREASCAL" in header:
            areascal = header["AREASCAL"]
        elif "AREASCAL" in data.colnames:
            areascal = data["AREASCAL"]
        else:
            raise ValueError("No AREASCAL found in the PHA file.")

        if header.get("HDUCLAS2") == "NET":
            flags.append("NET")

        kwargs = {
            "grouping": grouping,
            "quality": quality,
            "backfile": header.get("BACKFILE"),
            "respfile": header.get("RESPFILE"),
            "ancrfile": header.get("ANCRFILE"),
            "backscal": backscal,
            "areascal": areascal,
            "flags": flags,
        }

        return cls(data["CHANNEL"], data["COUNTS"], header["EXPOSURE"], **kwargs)

from_file(pha_file) classmethod

Load the data from a PHA file.

Parameters:

Name	Type	Description	Default
pha_file	str | PathLike	The PHA file path.	required

Source code in src/jaxspec/data/ogip.py

@classmethod
def from_file(cls, pha_file: str | os.PathLike):
    """
    Load the data from a PHA file.

    Parameters:
        pha_file: The PHA file path.
    """

    data = QTable.read(pha_file, "SPECTRUM")
    header = fits.getheader(pha_file, "SPECTRUM")
    flags = []

    if header.get("HDUCLAS3") == "RATE":
        raise ValueError(
            f"The HDUCLAS3={header.get('HDUCLAS3')} keyword in the PHA file is not supported."
            f"Please open an issue if this is required."
        )

    if header.get("HDUCLAS4") == "TYPE:II":
        raise ValueError(
            f"The HDUCLAS4={header.get('HDUCLAS4')} keyword in the PHA file is not supported."
            f"Please open an issue if this is required."
        )

    if header.get("GROUPING") == 0:
        grouping = None
    elif "GROUPING" in data.colnames:
        grouping = data["GROUPING"]
    else:
        raise ValueError("No grouping column found in the PHA file.")

    if header.get("QUALITY") == 0:
        quality = np.zeros(len(data["CHANNEL"]), dtype=bool)
    elif "QUALITY" in data.colnames:
        quality = data["QUALITY"]
    else:
        raise ValueError("No QUALITY column found in the PHA file.")

    if "BACKSCAL" in header:
        backscal = header["BACKSCAL"] * np.ones_like(data["CHANNEL"])
    elif "BACKSCAL" in data.colnames:
        backscal = data["BACKSCAL"]
    else:
        raise ValueError("No BACKSCAL found in the PHA file.")

    backscal = np.where(backscal == 0, 1.0, backscal)

    if "AREASCAL" in header:
        areascal = header["AREASCAL"]
    elif "AREASCAL" in data.colnames:
        areascal = data["AREASCAL"]
    else:
        raise ValueError("No AREASCAL found in the PHA file.")

    if header.get("HDUCLAS2") == "NET":
        flags.append("NET")

    kwargs = {
        "grouping": grouping,
        "quality": quality,
        "backfile": header.get("BACKFILE"),
        "respfile": header.get("RESPFILE"),
        "ancrfile": header.get("ANCRFILE"),
        "backscal": backscal,
        "areascal": areascal,
        "flags": flags,
    }

    return cls(data["CHANNEL"], data["COUNTS"], header["EXPOSURE"], **kwargs)

DataRMF

Class to handle RMF data defined with OGIP standards.

References

• The Calibration Requirements for Spectral Analysis (Definition of RMF and ARF file formats)
• The Calibration Requirements for Spectral Analysis Addendum: Changes log

Source code in src/jaxspec/data/ogip.py

class DataRMF:
    r"""
    Class to handle RMF data defined with OGIP standards.
    ??? info "References"
        * [The Calibration Requirements for Spectral Analysis (Definition of RMF and ARF file formats)](https://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/docs/memos/cal_gen_92_002/cal_gen_92_002.html)
        * [The Calibration Requirements for Spectral Analysis Addendum: Changes log](https://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/docs/memos/cal_gen_92_002a/cal_gen_92_002a.html)
    """

    def __init__(
        self,
        energ_lo,
        energ_hi,
        n_grp,
        f_chan,
        n_chan,
        matrix,
        channel,
        e_min,
        e_max,
        low_threshold=0.0,
    ):
        # RMF stuff
        self.energ_lo = energ_lo  # "Entry" energies
        self.energ_hi = energ_hi  # "Entry" energies
        self.n_grp = n_grp
        self.f_chan = f_chan
        self.n_chan = n_chan
        self.matrix_entry = matrix

        # Detector channels
        self.channel = channel
        self.e_min = e_min
        self.e_max = e_max

        # Prepare data for sparse matrix
        rows = []
        cols = []
        data = []

        for i, n_grp_val in enumerate(self.n_grp):
            base = 0

            if np.size(self.f_chan[i]) == 1:
                low = int(self.f_chan[i].ravel()[0])
                high = min(
                    int(self.f_chan[i].ravel()[0] + self.n_chan[i].ravel()[0]),
                    len(self.channel),
                )

                rows.extend([i] * (high - low))
                cols.extend(range(low, high))
                data.extend(self.matrix_entry[i][0 : high - low])

            else:
                for j in range(n_grp_val):
                    low = self.f_chan[i][j]
                    high = min(self.f_chan[i][j] + self.n_chan[i][j], len(self.channel))

                    rows.extend([i] * (high - low))
                    cols.extend(range(low, high))
                    data.extend(self.matrix_entry[i][base : base + self.n_chan[i][j]])

                    base += self.n_chan[i][j]

        # Convert lists to numpy arrays
        rows = np.array(rows)
        cols = np.array(cols)
        data = np.array(data)

        # Sometimes, zero elements are given in the matrix rows, so we get rid of them
        idxs = data > low_threshold

        # Create a COO sparse matrix and then convert to CSR for efficiency
        coo = sparse.COO(
            [rows[idxs], cols[idxs]], data[idxs], shape=(len(self.energ_lo), len(self.channel))
        )
        self.sparse_matrix = coo.T  # .tocsr()

    @property
    def matrix(self):
        return np.asarray(self.sparse_matrix.todense())

    @classmethod
    def from_file(cls, rmf_file: str | os.PathLike):
        """
        Load the data from an RMF file.

        Parameters:
            rmf_file: The RMF file path.
        """
        extension_names = [hdu[1] for hdu in fits.info(rmf_file, output=False)]

        if "MATRIX" in extension_names:
            matrix_extension = "MATRIX"

        elif "SPECRESP MATRIX" in extension_names:
            matrix_extension = "SPECRESP MATRIX"
            # raise NotImplementedError("SPECRESP MATRIX extension is not yet supported")

        else:
            raise ValueError("No MATRIX or SPECRESP MATRIX extension found in the RMF file")

        matrix_table = QTable.read(rmf_file, matrix_extension)
        ebounds_table = QTable.read(rmf_file, "EBOUNDS")

        matrix_header = fits.getheader(rmf_file, matrix_extension)

        f_chan_column_pos = list(matrix_table.columns).index("F_CHAN") + 1
        tlmin_fchan = int(matrix_header[f"TLMIN{f_chan_column_pos}"])

        return cls(
            matrix_table["ENERG_LO"],
            matrix_table["ENERG_HI"],
            matrix_table["N_GRP"],
            matrix_table["F_CHAN"] - tlmin_fchan,
            matrix_table["N_CHAN"],
            matrix_table["MATRIX"],
            ebounds_table["CHANNEL"],
            ebounds_table["E_MIN"],
            ebounds_table["E_MAX"],
        )

from_file(rmf_file) classmethod

Load the data from an RMF file.

Parameters:

Name	Type	Description	Default
rmf_file	str | PathLike	The RMF file path.	required

Source code in src/jaxspec/data/ogip.py

@classmethod
def from_file(cls, rmf_file: str | os.PathLike):
    """
    Load the data from an RMF file.

    Parameters:
        rmf_file: The RMF file path.
    """
    extension_names = [hdu[1] for hdu in fits.info(rmf_file, output=False)]

    if "MATRIX" in extension_names:
        matrix_extension = "MATRIX"

    elif "SPECRESP MATRIX" in extension_names:
        matrix_extension = "SPECRESP MATRIX"
        # raise NotImplementedError("SPECRESP MATRIX extension is not yet supported")

    else:
        raise ValueError("No MATRIX or SPECRESP MATRIX extension found in the RMF file")

    matrix_table = QTable.read(rmf_file, matrix_extension)
    ebounds_table = QTable.read(rmf_file, "EBOUNDS")

    matrix_header = fits.getheader(rmf_file, matrix_extension)

    f_chan_column_pos = list(matrix_table.columns).index("F_CHAN") + 1
    tlmin_fchan = int(matrix_header[f"TLMIN{f_chan_column_pos}"])

    return cls(
        matrix_table["ENERG_LO"],
        matrix_table["ENERG_HI"],
        matrix_table["N_GRP"],
        matrix_table["F_CHAN"] - tlmin_fchan,
        matrix_table["N_CHAN"],
        matrix_table["MATRIX"],
        ebounds_table["CHANNEL"],
        ebounds_table["E_MIN"],
        ebounds_table["E_MAX"],
    )