drift.core.beamtransfer
+Calculation and management of Beam Transfer matrices
+Functions
+
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++ |
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+Find the inverse of A. |
+
Classes
+
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+A class for reading and writing Beam Transfer matrices from disk. |
+
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+BeamTransfer class that performs the old temperature only SVD. |
+
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+BeamTransfer class that performs the old temperature only SVD. |
+
-
+
- +class drift.core.beamtransfer.BeamTransfer(directory, telescope=None) +
Bases:
+ReaderA class for reading and writing Beam Transfer matrices from disk.
+In addition this provides methods for projecting vectors and matrices +between the sky and the telescope basis.
+-
+
- Parameters: +
-
+
directory (string) – Path of directory to read and write Beam Transfers from.
+telescope (drift.core.telescope.TransitTelescope, optional) – Telescope object to use for calculation. If None (default), try to +load a cached version from the given directory.
+
+
-
+
- +mem_chunk +
The amount of memory to use per process in this calculation in GB. This is a +target and not a strict upper limit. This will change the number of chunks the +calculation is split into. Default is 3 GB.
+-
+
- Type: +
float
+
+
-
+
- +svcut +
The relative precision below the maximum singular value to exclude low +sensitivity SVD modes. This can be dynamically changed as it is evaluated +when performing projections.
+-
+
- Type: +
float
+
+
-
+
- +polsvcut +
The relative precision below the maximum value to assume the polarisation +sensitivity is zero. This is used to find the polarisation null space. This +is used to generate the cached SVD modes and so cannot be changed after they +are generated.
+-
+
- Type: +
float
+
+
-
+
- +truncate +
Whether precision truncation of the beam transfer matrices should be done.
+-
+
- Type: +
bool
+
+
-
+
- +truncate_rel +
The relative per element precision to use for the truncation.
+-
+
- Type: +
float
+
+
-
+
- +truncate_maxl +
The truncation precision to use relative the maximum value for all l’s of +that mode.
+-
+
- Type: +
float
+
+
-
+
- +chunk_cache_size +
The size of the per m-file HDF5 chunk cache. Default is 128 MB.
+-
+
- Type: +
int
+
+
-
+
- +beam_m(mi: int, fi: int | None = None) ndarray +
Fetch the beam transfer matrix for a given m.
+-
+
- Parameters: +
-
+
mi (integer) – m-mode to fetch.
+fi (integer) – frequency block to fetch. fi=None (default) returns all.
+
+- Returns: +
beam
+
+- Return type: +
np.ndarray (nfreq, 2, npairs, npol_sky, lmax+1)
+
+
-
+
- +beam_singularvalues(mi: int) ndarray +
Fetch the vector of beam singular values for a given m.
+-
+
- Parameters: +
mi (integer) – m-mode to fetch.
+
+- Returns: +
beam
+
+- Return type: +
np.ndarray (nfreq, svd_len)
+
+
-
+
- +beam_svd(mi: int, fi: int | None = None) ndarray +
Fetch the SVD beam transfer matrix (S V^H) for a given m. This SVD beam +transfer projects from the sky into the SVD basis.
+This returns the full SVD spectrum. Cutting based on SVD value must be +done by other routines (see project*svd methods).
+-
+
- Parameters: +
-
+
mi (integer) – m-mode to fetch.
+fi (integer) – frequency block to fetch. fi=None (default) returns all.
+
+- Returns: +
beam
+
+- Return type: +
np.ndarray (nfreq, svd_len, npol_sky, lmax+1)
+
+
-
+
- +beam_ut(mi: int, fi: int | None = None) ndarray +
Fetch the SVD beam transfer matrix (U^H) for a given m. This SVD beam +transfer projects from the telescope space into the SVD basis.
+This returns the full SVD spectrum. Cutting based on SVD value must be +done by other routines (see project*svd methods).
+-
+
- Parameters: +
-
+
mi (integer) – m-mode to fetch.
+fi (integer) – frequency block to fetch. fi=None (default) returns all.
+
+- Returns: +
beam
+
+- Return type: +
np.ndarray (nfreq, svd_len, ntel)
+
+
-
+
- +generate(regen=False, skip_svd=False, skip_svd_inv=False) +
Save out all beam transfer matrices to disk.
+-
+
- Parameters: +
-
+
regen (boolean, optional) – Force regeneration even if cache files exist (default: False).
+skip_svd (boolen, optional) – Skip SVD beam generation. Saves time and space if you are only map making.
+
+
-
+
- +generate_cache(regen=False, skip_svd=False, skip_svd_inv=False) +
Save out all beam transfer matrices to disk.
+-
+
- Parameters: +
-
+
regen (boolean, optional) – Force regeneration even if cache files exist (default: False).
+skip_svd (boolen, optional) – Skip SVD beam generation. Saves time and space if you are only map making.
+
+
-
+
- +invbeam_m(mi) +
Pseudo-inverse of the beam (for a given m).
+Uses the Moore-Penrose Pseudo-inverse as the optimal inverse for +reconstructing the data. No single option as this only makes sense +when combined.
+-
+
- Parameters: +
mi (integer) – m-mode to calculate.
+
+- Returns: +
invbeam
+
+- Return type: +
np.ndarray (nfreq, npol_sky, lmax+1, 2, npairs)
+
+
-
+
- +invbeam_svd(mi: int, fi: int | None = None) ndarray +
Fetch the SVD beam transfer matrix (S V^H) for a given m. This SVD beam +transfer projects from the sky into the SVD basis.
+This returns the full SVD spectrum. Cutting based on SVD value must be +done by other routines (see project*svd methods).
+-
+
- Parameters: +
-
+
mi (integer) – m-mode to fetch.
+fi (integer) – frequency block to fetch. fi=None (default) returns all.
+
+- Returns: +
beam
+
+- Return type: +
np.ndarray (nfreq, svd_len, npol_sky, lmax+1)
+
+
-
+
- +ndof(mi) +
The number of degrees of freedom at a given m.
+
-
+
- +property nfreq +
Number of frequencies measured.
+
-
+
- +property nsky +
Degrees of freedom on the sky at each frequency.
+
-
+
- +property ntel +
Degrees of freedom measured by the telescope (per frequency)
+
-
+
- +project_matrix_diagonal_telescope_to_svd(mi, dmat) +
Project a diagonal matrix from the telescope basis into the SVD basis.
+This slightly specialised routine is for projecting the noise +covariance into the SVD space.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+mat (np.ndarray) – Sky matrix packed as [nfreq, ntel]
+
+- Returns: +
tmat – Covariance in SVD basis.
+
+- Return type: +
np.ndarray [nsvd, nsvd]
+
+
-
+
- +project_matrix_forward(mi, mat) +
Project a covariance matrix from the sky into the visibility basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+mat (np.ndarray) – Sky matrix packed as [pol, pol, l, freq, freq]
+
+- Returns: +
tmat – Covariance in telescope basis.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_matrix_sky_to_svd(mi, mat, temponly=False) +
Project a covariance matrix from the sky into the SVD basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+mat (np.ndarray) – Sky matrix packed as [pol, pol, l, freq, freq]. Must have pol +indices even if temponly=True.
+temponly (boolean) – Force projection of temperature (TT) part only (default: False)
+
+- Returns: +
tmat – Covariance in SVD basis.
+
+- Return type: +
np.ndarray [nsvd, nsvd]
+
+
-
+
- +project_matrix_sky_to_telescope(mi, mat) +
Project a covariance matrix from the sky into the visibility basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+mat (np.ndarray) – Sky matrix packed as [pol, pol, l, freq, freq]
+
+- Returns: +
tmat – Covariance in telescope basis.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_backward(mi, vec) +
Invert a vector from the telescope space onto the sky. This is the +map-making process.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Sky data vector packed as [freq, baseline, polarisation]
+
+- Returns: +
tvec – Sky vector to return.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_forward(mi, vec) +
Project a vector from the sky into the visibility basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Sky data vector packed as [nfreq, npol, lmax+1]
+
+- Returns: +
tvec – Telescope vector to return.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_sky_to_svd(mi, vec, temponly=False) +
Project a vector from the the sky into the SVD basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Sky data vector packed as [nfreq, lmax+1]
+temponly (boolean) – Force projection of temperature part only (default: False)
+
+- Returns: +
svec – SVD vector to return.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_sky_to_telescope(mi, vec) +
Project a vector from the sky into the visibility basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Sky data vector packed as [nfreq, npol, lmax+1]
+
+- Returns: +
tvec – Telescope vector to return.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_svd_to_sky(mi, vec, temponly=False, conj=False) +
Project a vector from the the sky into the SVD basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Sky data vector packed as [nfreq, lmax+1]
+temponly (boolean) – Force projection of temperature part only (default: False)
+conj (boolean) – Reverse projection by applying conjugation (as opposed to pseudo- +inverse). Default is False.
+
+- Returns: +
svec – SVD vector to return.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_svd_to_telescope(mi, svec) +
Map a vector from the SVD basis into the original data basis.
+This projection may be lose information about the sky, depending on the +polarisation filtering. This essentially uses the pseudo-inverse which +is simply related to the original projection matrix.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+svec (np.ndarray) – SVD data vector.
+
+- Returns: +
vec – Data vector to return.
+
+- Return type: +
np.ndarray[freq, sign, baseline]
+
+
-
+
- +project_vector_telescope_to_sky(mi, vec) +
Invert a vector from the telescope space onto the sky. This is the +map-making process.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Sky data vector packed as [freq, baseline, polarisation]
+
+- Returns: +
tvec – Sky vector to return.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_telescope_to_svd(mi, vec) +
Map a vector from the telescope space into the SVD basis.
+This projection may be lose information about the sky, depending on +the polarisation filtering.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Telescope data vector packed as [freq, baseline, polarisation]
+
+- Returns: +
svec – SVD vector to return.
+
+- Return type: +
np.ndarray[svdnum]
+
+
-
+
- +svd_all() +
Collects the full SVD spectrum for all m-modes.
+Reads in from file on disk.
+-
+
- Returns: +
svarray – The full set of singular values across all m-modes.
+
+- Return type: +
np.ndarray[mmax+1, nfreq, svd_len]
+
+
-
+
- +property svd_len +
The size of the SVD output matrices.
+
-
+
- +class drift.core.beamtransfer.BeamTransferFullSVD(directory, telescope=None) +
Bases:
+BeamTransferBeamTransfer class that performs the old temperature only SVD.
+-
+
- +property svd_len +
The size of the SVD output matrices.
+
-
+
- +class drift.core.beamtransfer.BeamTransferNoSVD(directory, telescope=None) +
Bases:
+BeamTransfer-
+
- +beam_svd(mi, *args, **kwargs) +
Fetch the SVD beam transfer matrix (S V^H) for a given m. This SVD beam +transfer projects from the sky into the SVD basis.
+This returns the full SVD spectrum. Cutting based on SVD value must be +done by other routines (see project*svd methods).
+-
+
- Parameters: +
-
+
mi (integer) – m-mode to fetch.
+fi (integer) – frequency block to fetch. fi=None (default) returns all.
+
+- Returns: +
beam
+
+- Return type: +
np.ndarray (nfreq, svd_len, npol_sky, lmax+1)
+
+
-
+
- +ndof(mi, *args, **kwargs) +
The number of degrees of freedom at a given m.
+
-
+
- +project_matrix_diagonal_telescope_to_svd(mi, dmat, *args, **kwargs) +
Project a diagonal matrix from the telescope basis into the SVD basis.
+This slightly specialised routine is for projecting the noise +covariance into the SVD space.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+mat (np.ndarray) – Sky matrix packed as [nfreq, ntel]
+
+- Returns: +
tmat – Covariance in SVD basis.
+
+- Return type: +
np.ndarray [nsvd, nsvd]
+
+
-
+
- +project_matrix_sky_to_svd(mi, mat, *args, **kwargs) +
Project a covariance matrix from the sky into the SVD basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+mat (np.ndarray) – Sky matrix packed as [pol, pol, l, freq, freq]. Must have pol +indices even if temponly=True.
+temponly (boolean) – Force projection of temperature (TT) part only (default: False)
+
+- Returns: +
tmat – Covariance in SVD basis.
+
+- Return type: +
np.ndarray [nsvd, nsvd]
+
+
-
+
- +project_vector_sky_to_svd(mi, vec, *args, **kwargs) +
Project a vector from the the sky into the SVD basis.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Sky data vector packed as [nfreq, lmax+1]
+temponly (boolean) – Force projection of temperature part only (default: False)
+
+- Returns: +
svec – SVD vector to return.
+
+- Return type: +
np.ndarray
+
+
-
+
- +project_vector_telescope_to_svd(mi, vec, *args, **kwargs) +
Map a vector from the telescope space into the SVD basis.
+This projection may be lose information about the sky, depending on +the polarisation filtering.
+-
+
- Parameters: +
-
+
mi (integer) – Mode index to fetch for.
+vec (np.ndarray) – Telescope data vector packed as [freq, baseline, polarisation]
+
+- Returns: +
svec – SVD vector to return.
+
+- Return type: +
np.ndarray[svdnum]
+
+
-
+
- +class drift.core.beamtransfer.BeamTransferTempSVD(directory, telescope=None) +
Bases:
+BeamTransferBeamTransfer class that performs the old temperature only SVD.
+
-
+
- +drift.core.beamtransfer.svd_gen(A, errmsg=None, *args, **kwargs) +
Find the inverse of A.
+If a standard matrix inverse has issues try using the pseudo-inverse.
+-
+
- Parameters: +
A (np.ndarray) – Matrix to invert.
+
+- Returns: +
inv
+
+- Return type: +
np.ndarray
+
+
