Source code for utils

# -*- mode: python; coding: utf-8 -*-
# Copyright (c) 2018 Radio Astronomy Software Group
# Licensed under the 2-clause BSD License

"""Commonly used utility functions."""
from __future__ import absolute_import, division, print_function

import numpy as np
import warnings
import copy
from scipy.spatial.distance import pdist, squareform
from astropy.time import Time
from astropy.coordinates import Angle
from astropy.utils import iers

from collections.abc import Iterable

# parameters for transforming between xyz & lat/lon/alt
gps_b = 6356752.31424518
gps_a = 6378137
e_squared = 6.69437999014e-3
e_prime_squared = 6.73949674228e-3


def _str_to_bytes(s):
    warnings.warn(
        "_str_to_bytes is deprecated and will be removed in pyuvdata version 2.2. "
        "For an input string s, this function is a thin wrapper on s.encode('utf8'). "
        "The use of encode is preferred over calling this function.",
        DeprecationWarning,
    )
    return s.encode("utf8")


def _bytes_to_str(b):
    warnings.warn(
        "_bytes_to_str is deprecated and will be removed in pyuvdata version 2.2. "
        "For an input string s, this function is a thin wrapper on s.decode('utf8'). "
        "The use of decode is preferred over calling this function.",
        DeprecationWarning,
    )
    return b.decode("utf8")


__all__ = [
    "POL_STR2NUM_DICT",
    "POL_NUM2STR_DICT",
    "CONJ_POL_DICT",
    "JONES_STR2NUM_DICT",
    "JONES_NUM2STR_DICT",
    "LatLonAlt_from_XYZ",
    "XYZ_from_LatLonAlt",
    "rotECEF_from_ECEF",
    "ECEF_from_rotECEF",
    "ENU_from_ECEF",
    "ECEF_from_ENU",
    "phase_uvw",
    "unphase_uvw",
    "uvcalibrate",
    "apply_uvflag",
    "get_lst_for_time",
    "polstr2num",
    "polnum2str",
    "jstr2num",
    "jnum2str",
    "parse_polstr",
    "parse_jpolstr",
    "conj_pol",
    "reorder_conj_pols",
    "baseline_to_antnums",
    "antnums_to_baseline",
    "baseline_index_flip",
    "get_baseline_redundancies",
    "get_antenna_redundancies",
    "collapse",
    "mean_collapse",
    "absmean_collapse",
    "quadmean_collapse",
    "or_collapse",
    "and_collapse",
]

# fmt: off
# polarization constants
# maps polarization strings to polarization integers
POL_STR2NUM_DICT = {'pI': 1, 'pQ': 2, 'pU': 3, 'pV': 4,
                    'I': 1, 'Q': 2, 'U': 3, 'V': 4,  # support straight stokes names
                    'rr': -1, 'll': -2, 'rl': -3, 'lr': -4,
                    'xx': -5, 'yy': -6, 'xy': -7, 'yx': -8}
# maps polarization integers to polarization strings
POL_NUM2STR_DICT = {1: 'pI', 2: 'pQ', 3: 'pU', 4: 'pV',
                    -1: 'rr', -2: 'll', -3: 'rl', -4: 'lr',
                    -5: 'xx', -6: 'yy', -7: 'xy', -8: 'yx'}

# maps how polarizations change when antennas are swapped
CONJ_POL_DICT = {'xx': 'xx', 'yy': 'yy', 'xy': 'yx', 'yx': 'xy',
                 'ee': 'ee', 'nn': 'nn', 'en': 'ne', 'ne': 'en',
                 'rr': 'rr', 'll': 'll', 'rl': 'lr', 'lr': 'rl',
                 'I': 'I', 'Q': 'Q', 'U': 'U', 'V': 'V',
                 'pI': 'pI', 'pQ': 'pQ', 'pU': 'pU', 'pV': 'pV'}

# maps jones matrix element strings to jones integers
# Add entries that don't start with 'J' to allow shorthand versions
JONES_STR2NUM_DICT = {'Jxx': -5, 'Jyy': -6, 'Jxy': -7, 'Jyx': -8,
                      'xx': -5, 'x': -5, 'yy': -6, 'y': -6, 'xy': -7, 'yx': -8,
                      'Jrr': -1, 'Jll': -2, 'Jrl': -3, 'Jlr': -4,
                      'rr': -1, 'r': -1, 'll': -2, 'l': -2, 'rl': -3, 'lr': -4}
# maps jones integers to jones matrix element strings
JONES_NUM2STR_DICT = {-1: 'Jrr', -2: 'Jll', -3: 'Jrl', -4: 'Jlr',
                      -5: 'Jxx', -6: 'Jyy', -7: 'Jxy', -8: 'Jyx'}
# fmt: on


def _get_iterable(x):
    """Return iterable version of input."""
    if isinstance(x, Iterable):
        return x
    else:
        return (x,)


def _fits_gethduaxis(hdu, axis):
    """
    Make axis arrays for fits files.

    Parameters
    ----------
    hdu : astropy.io.fits HDU object
        The HDU to make an axis array for.
    axis : int
        The axis number of interest (1-based).

    Returns
    -------
    ndarray of float
        Array of values for the specified axis.

    """
    ax = str(axis)
    axis_num = hdu.header["NAXIS" + ax]
    val = hdu.header["CRVAL" + ax]
    delta = hdu.header["CDELT" + ax]
    index = hdu.header["CRPIX" + ax] - 1

    return delta * (np.arange(axis_num) - index) + val


def _fits_indexhdus(hdulist):
    """
    Get a dict of table names and HDU numbers from a FITS HDU list.

    Parameters
    ----------
    hdulist : list of astropy.io.fits HDU objects
        List of HDUs to get names for

    Returns
    -------
    dict
        dictionary with table names as keys and HDU number as values.

    """
    tablenames = {}
    for i in range(len(hdulist)):
        try:
            tablenames[hdulist[i].header["EXTNAME"]] = i
        except (KeyError):
            continue
    return tablenames


def _check_history_version(history, version_string):
    """Check if version_string is present in history string."""
    if version_string.replace(" ", "") in history.replace("\n", "").replace(" ", ""):
        return True
    else:
        return False


def _check_histories(history1, history2):
    """Check if two histories are the same."""
    if history1.replace("\n", "").replace(" ", "") == history2.replace(
        "\n", ""
    ).replace(" ", ""):
        return True
    else:
        return False


def _combine_histories(history1, history2):
    """Combine histories with minimal repeats."""
    hist2_words = history2.split(" ")
    add_hist = ""
    test_hist1 = " " + history1 + " "
    for i, word in enumerate(hist2_words):
        if " " + word + " " not in test_hist1:
            add_hist += " " + word
            keep_going = i + 1 < len(hist2_words)
            while keep_going:
                if (hist2_words[i + 1] == " ") or (
                    " " + hist2_words[i + 1] + " " not in test_hist1
                ):
                    add_hist += " " + hist2_words[i + 1]
                    del hist2_words[i + 1]
                    keep_going = i + 1 < len(hist2_words)
                else:
                    keep_going = False

    return history1 + add_hist


[docs]def baseline_to_antnums(baseline, Nants_telescope): """ Get the antenna numbers corresponding to a given baseline number. Parameters ---------- baseline : int or array_like of ints baseline number Nants_telescope : int number of antennas Returns ------- int or array_like of int first antenna number(s) int or array_like of int second antenna number(s) """ if Nants_telescope > 2048: raise Exception( "error Nants={Nants}>2048 not " "supported".format(Nants=Nants_telescope) ) baseline = np.asarray(baseline, dtype=np.int64) if np.min(baseline) > 2 ** 16: ant2 = (baseline - 2 ** 16) % 2048 - 1 ant1 = (baseline - 2 ** 16 - (ant2 + 1)) / 2048 - 1 else: ant2 = (baseline) % 256 - 1 ant1 = (baseline - (ant2 + 1)) / 256 - 1 return np.int32(ant1), np.int32(ant2)
[docs]def antnums_to_baseline(ant1, ant2, Nants_telescope, attempt256=False): """ Get the baseline number corresponding to two given antenna numbers. Parameters ---------- ant1 : int or array_like of int first antenna number ant2 : int or array_like of int second antenna number Nants_telescope : int number of antennas attempt256 : bool Option to try to use the older 256 standard used in many uvfits files (will use 2048 standard if there are more than 256 antennas). Default is False. Returns ------- int or array of int baseline number corresponding to the two antenna numbers. """ ant1, ant2 = np.int64((ant1, ant2)) if Nants_telescope is not None and Nants_telescope > 2048: raise Exception( "cannot convert ant1, ant2 to a baseline index " "with Nants={Nants}>2048.".format(Nants=Nants_telescope) ) if attempt256: if np.max(ant1) < 255 and np.max(ant2) < 255: return 256 * (ant1 + 1) + (ant2 + 1) else: print("Max antnums are {} and {}".format(np.max(ant1), np.max(ant2))) message = ( "antnums_to_baseline: found > 256 antennas, using " "2048 baseline indexing. Beware compatibility " "with CASA etc" ) warnings.warn(message) baseline = 2048 * (ant1 + 1) + (ant2 + 1) + 2 ** 16 if isinstance(baseline, np.ndarray): return np.asarray(baseline, dtype=np.int64) else: return np.int64(baseline)
[docs]def baseline_index_flip(baseline, Nants_telescope): """Change baseline number to reverse antenna order.""" ant1, ant2 = baseline_to_antnums(baseline, Nants_telescope) return antnums_to_baseline(ant2, ant1, Nants_telescope)
def _x_orientation_rep_dict(x_orientation): """Create replacement dict based on x_orientation.""" if x_orientation.lower() == "east" or x_orientation.lower() == "e": return {"x": "e", "y": "n"} elif x_orientation.lower() == "north" or x_orientation.lower() == "n": return {"x": "n", "y": "e"} else: raise ValueError("x_orientation not recognized.")
[docs]def polstr2num(pol, x_orientation=None): """ Convert polarization str to number according to AIPS Memo 117. Prefer 'pI', 'pQ', 'pU' and 'pV' to make it clear that these are pseudo-Stokes, not true Stokes, but also supports 'I', 'Q', 'U', 'V'. Parameters ---------- pol : str polarization string x_orientation : str, optional Orientation of the physical dipole corresponding to what is labelled as the x polarization ("east" or "north") to allow for converting from E/N strings. See corresonding parameter on UVData for more details. Returns ------- int Number corresponding to string Raises ------ ValueError If the pol string cannot be converted to a polarization number. Warns ----- UserWarning If the x_orientation not recognized. """ dict_use = copy.deepcopy(POL_STR2NUM_DICT) if x_orientation is not None: try: rep_dict = _x_orientation_rep_dict(x_orientation) for key, value in POL_STR2NUM_DICT.items(): new_key = key.replace("x", rep_dict["x"]).replace("y", rep_dict["y"]) dict_use[new_key] = value except ValueError: warnings.warn("x_orientation not recognized.") poldict = {k.lower(): v for k, v in dict_use.items()} if isinstance(pol, str): out = poldict[pol.lower()] elif isinstance(pol, Iterable): out = [poldict[key.lower()] for key in pol] else: raise ValueError( "Polarization {p} cannot be converted to a polarization number.".format( p=pol ) ) return out
[docs]def polnum2str(num, x_orientation=None): """ Convert polarization number to str according to AIPS Memo 117. Uses 'pI', 'pQ', 'pU' and 'pV' to make it clear that these are pseudo-Stokes, not true Stokes Parameters ---------- num : int polarization number x_orientation : str, optional Orientation of the physical dipole corresponding to what is labelled as the x polarization ("east" or "north") to convert to E/N strings. See corresonding parameter on UVData for more details. Returns ------- str String corresponding to polarization number Raises ------ ValueError If the polarization number cannot be converted to a polarization string. Warns ----- UserWarning If the x_orientation not recognized. """ dict_use = copy.deepcopy(POL_NUM2STR_DICT) if x_orientation is not None: try: rep_dict = _x_orientation_rep_dict(x_orientation) for key, value in POL_NUM2STR_DICT.items(): new_val = value.replace("x", rep_dict["x"]).replace("y", rep_dict["y"]) dict_use[key] = new_val except ValueError: warnings.warn("x_orientation not recognized.") if isinstance(num, (int, np.int32, np.int64)): out = dict_use[num] elif isinstance(num, Iterable): out = [dict_use[i] for i in num] else: raise ValueError( "Polarization {p} cannot be converted to string.".format(p=num) ) return out
[docs]def jstr2num(jstr, x_orientation=None): """ Convert jones polarization str to number according to calfits memo. Parameters ---------- jstr : str antenna (jones) polarization string x_orientation : str, optional Orientation of the physical dipole corresponding to what is labelled as the x polarization ("east" or "north") to allow for converting from E/N strings. See corresonding parameter on UVData for more details. Returns ------- int antenna (jones) polarization number corresponding to string Raises ------ ValueError If the jones string cannot be converted to a polarization number. Warns ----- UserWarning If the x_orientation not recognized. """ dict_use = copy.deepcopy(JONES_STR2NUM_DICT) if x_orientation is not None: try: rep_dict = _x_orientation_rep_dict(x_orientation) for key, value in JONES_STR2NUM_DICT.items(): new_key = key.replace("x", rep_dict["x"]).replace("y", rep_dict["y"]) dict_use[new_key] = value except ValueError: warnings.warn("x_orientation not recognized.") jdict = {k.lower(): v for k, v in dict_use.items()} if isinstance(jstr, str): out = jdict[jstr.lower()] elif isinstance(jstr, Iterable): out = [jdict[key.lower()] for key in jstr] else: raise ValueError( "Jones polarization {j} cannot be converted to index.".format(j=jstr) ) return out
[docs]def jnum2str(jnum, x_orientation=None): """ Convert jones polarization number to str according to calfits memo. Parameters ---------- num : int antenna (jones) polarization number x_orientation : str, optional Orientation of the physical dipole corresponding to what is labelled as the x polarization ("east" or "north") to convert to E/N strings. See corresonding parameter on UVData for more details. Returns ------- str antenna (jones) polarization string corresponding to number Raises ------ ValueError If the jones polarization number cannot be converted to a jones polarization string. Warns ----- UserWarning If the x_orientation not recognized. """ dict_use = copy.deepcopy(JONES_NUM2STR_DICT) if x_orientation is not None: try: rep_dict = _x_orientation_rep_dict(x_orientation) for key, value in JONES_NUM2STR_DICT.items(): new_val = value.replace("x", rep_dict["x"]).replace("y", rep_dict["y"]) dict_use[key] = new_val except ValueError: warnings.warn("x_orientation not recognized.") if isinstance(jnum, (int, np.int32, np.int64)): out = dict_use[jnum] elif isinstance(jnum, Iterable): out = [dict_use[i] for i in jnum] else: raise ValueError( "Jones polarization {j} cannot be converted to string.".format(j=jnum) ) return out
[docs]def parse_polstr(polstr, x_orientation=None): """ Parse a polarization string and return pyuvdata standard polarization string. See utils.POL_STR2NUM_DICT for options. Parameters ---------- polstr : str polarization string x_orientation : str, optional Orientation of the physical dipole corresponding to what is labelled as the x polarization ("east" or "north") to allow for converting from E/N strings. See corresonding parameter on UVData for more details. Returns ------- str AIPS Memo 117 standard string Raises ------ ValueError If the pol string cannot be converted to a polarization number. Warns ----- UserWarning If the x_orientation not recognized. """ return polnum2str( polstr2num(polstr, x_orientation=x_orientation), x_orientation=x_orientation )
[docs]def parse_jpolstr(jpolstr, x_orientation=None): """ Parse a Jones polarization string and return pyuvdata standard jones string. See utils.JONES_STR2NUM_DICT for options. Parameters ---------- jpolstr : str Jones polarization string Returns ------- str calfits memo standard string Raises ------ ValueError If the jones string cannot be converted to a polarization number. Warns ----- UserWarning If the x_orientation not recognized. """ return jnum2str( jstr2num(jpolstr, x_orientation=x_orientation), x_orientation=x_orientation )
[docs]def conj_pol(pol): """ Return the polarization for the conjugate baseline. For example, (1, 2, 'xy') = conj(2, 1, 'yx'). The returned polarization is determined by assuming the antenna pair is reversed in the data, and finding the correct polarization correlation which will yield the requested baseline when conjugated. Note this means changing the polarization for linear cross-pols, but keeping auto-pol (e.g. xx) and Stokes the same. Parameters ---------- pol : str or int Polarization string or integer. Returns ------- cpol : str or int Polarization as if antennas are swapped (type matches input) """ cpol_dict = {k.lower(): v for k, v in CONJ_POL_DICT.items()} if isinstance(pol, str): cpol = cpol_dict[pol.lower()] elif isinstance(pol, Iterable): cpol = [conj_pol(p) for p in pol] elif isinstance(pol, (int, np.int32, np.int64)): cpol = polstr2num(cpol_dict[polnum2str(pol).lower()]) else: raise ValueError("Polarization not recognized, cannot be conjugated.") return cpol
[docs]def reorder_conj_pols(pols): """ Reorder multiple pols, swapping pols that are conjugates of one another. For example ('xx', 'xy', 'yx', 'yy') -> ('xx', 'yx', 'xy', 'yy') This is useful for the _key2inds function in the case where an antenna pair is specified but the conjugate pair exists in the data. The conjugated data should be returned in the order of the polarization axis, so after conjugating the data, the pols need to be reordered. For example, if a file contains antpair (0, 1) and pols 'xy' and 'yx', but the user requests antpair (1, 0), they should get: [(1x, 0y), (1y, 0x)] = [conj(0y, 1x), conj(0x, 1y)] Parameters ---------- pols : array_like of str or int Polarization array (strings or ints). Returns ------- conj_order : ndarray of int Indices to reorder polarization array. """ if not isinstance(pols, Iterable): raise ValueError("reorder_conj_pols must be given an array of polarizations.") cpols = np.array([conj_pol(p) for p in pols]) # Array needed for np.where conj_order = [np.where(cpols == p)[0][0] if p in cpols else -1 for p in pols] if -1 in conj_order: raise ValueError( "Not all conjugate pols exist in the polarization array provided." ) return conj_order
[docs]def LatLonAlt_from_XYZ(xyz, check_acceptability=True): """ Calculate lat/lon/alt from ECEF x,y,z. Parameters ---------- xyz : ndarray of float numpy array, shape (Npts, 3), with ECEF x,y,z coordinates. check_acceptability : bool Flag to check XYZ coordinates are reasonable. Returns ------- latitude : ndarray or float latitude, numpy array (if Npts > 1) or value (if Npts = 1) in radians longitude : ndarray or float longitude, numpy array (if Npts > 1) or value (if Npts = 1) in radians altitude : ndarray or float altitude, numpy array (if Npts > 1) or value (if Npts = 1) in meters """ # convert to a numpy array xyz = np.array(xyz) if xyz.ndim > 1 and xyz.shape[1] != 3: raise ValueError("The expected shape of ECEF xyz array is (Npts, 3).") else: xyz_use = xyz if xyz_use.ndim == 1: xyz_use = xyz_use[np.newaxis, :] # checking for acceptable values if check_acceptability: if np.any(np.linalg.norm(xyz_use, axis=1) < 6.35e6) or np.any( np.linalg.norm(xyz_use, axis=1) > 6.39e6 ): raise ValueError("xyz values should be ECEF x, y, z coordinates in meters") # see wikipedia geodetic_datum and Datum transformations of # GPS positions PDF in docs/references folder gps_p = np.sqrt(xyz_use[:, 0] ** 2 + xyz_use[:, 1] ** 2) gps_theta = np.arctan2(xyz_use[:, 2] * gps_a, gps_p * gps_b) latitude = np.arctan2( xyz_use[:, 2] + e_prime_squared * gps_b * np.sin(gps_theta) ** 3, gps_p - e_squared * gps_a * np.cos(gps_theta) ** 3, ) longitude = np.arctan2(xyz_use[:, 1], xyz_use[:, 0]) gps_n = gps_a / np.sqrt(1 - e_squared * np.sin(latitude) ** 2) altitude = (gps_p / np.cos(latitude)) - gps_n if xyz.ndim == 1: longitude = longitude[0] latitude = latitude[0] altitude = altitude[0] return latitude, longitude, altitude
[docs]def XYZ_from_LatLonAlt(latitude, longitude, altitude): """ Calculate ECEF x,y,z from lat/lon/alt values. Parameters ---------- latitude : ndarray or float latitude, numpy array (if Npts > 1) or value (if Npts = 1) in radians longitude : ndarray or float longitude, numpy array (if Npts > 1) or value (if Npts = 1) in radians altitude : ndarray or float altitude, numpy array (if Npts > 1) or value (if Npts = 1) in meters Returns ------- xyz : ndarray of float numpy array, shape (Npts, 3), with ECEF x,y,z coordinates. """ latitude = np.array(latitude) longitude = np.array(longitude) altitude = np.array(altitude) n_pts = latitude.size if longitude.size != n_pts: raise ValueError( "latitude, longitude and altitude must all have the same length" ) if altitude.size != n_pts: raise ValueError( "latitude, longitude and altitude must all have the same length" ) # see wikipedia geodetic_datum and Datum transformations of # GPS positions PDF in docs/references folder gps_n = gps_a / np.sqrt(1 - e_squared * np.sin(latitude) ** 2) xyz = np.zeros((n_pts, 3)) xyz[:, 0] = (gps_n + altitude) * np.cos(latitude) * np.cos(longitude) xyz[:, 1] = (gps_n + altitude) * np.cos(latitude) * np.sin(longitude) xyz[:, 2] = (gps_b ** 2 / gps_a ** 2 * gps_n + altitude) * np.sin(latitude) xyz = np.squeeze(xyz) return xyz
[docs]def rotECEF_from_ECEF(xyz, longitude): """ Get rotated ECEF positions such that the x-axis goes through the longitude. Miriad and uvfits expect antenna positions in this frame (with longitude of the array center/telescope location) Parameters ---------- xyz : ndarray of float numpy array, shape (Npts, 3), with ECEF x,y,z coordinates. longitude : float longitude in radians to rotate coordinates to (usually the array center/telescope location). Returns ------- ndarray of float Rotated ECEF coordinates, shape (Npts, 3). """ angle = -1 * longitude rot_matrix = np.array( [ [np.cos(angle), -1 * np.sin(angle), 0], [np.sin(angle), np.cos(angle), 0], [0, 0, 1], ] ) return rot_matrix.dot(xyz.T).T
[docs]def ECEF_from_rotECEF(xyz, longitude): """ Calculate ECEF from a rotated ECEF (Inverse of rotECEF_from_ECEF). Parameters ---------- xyz : ndarray of float numpy array, shape (Npts, 3), with rotated ECEF x,y,z coordinates. longitude : float longitude in radians giving the x direction of the rotated coordinates (usually the array center/telescope location). Returns ------- ndarray of float ECEF coordinates, shape (Npts, 3). """ angle = longitude rot_matrix = np.array( [ [np.cos(angle), -1 * np.sin(angle), 0], [np.sin(angle), np.cos(angle), 0], [0, 0, 1], ] ) return rot_matrix.dot(xyz.T).T
[docs]def ENU_from_ECEF(xyz, latitude, longitude, altitude): """ Calculate local ENU (east, north, up) coordinates from ECEF coordinates. Parameters ---------- xyz : ndarray of float numpy array, shape (Npts, 3), with ECEF x,y,z coordinates. latitude : float Latitude of center of ENU coordinates in radians. longitude : float Longitude of center of ENU coordinates in radians. altitude : float Altitude of center of ENU coordinates in radians. Returns ------- ndarray of float numpy array, shape (Npts, 3), with local ENU coordinates """ xyz = np.array(xyz) if xyz.ndim > 1 and xyz.shape[1] != 3: raise ValueError("The expected shape of ECEF xyz array is (Npts, 3).") xyz_in = xyz if xyz_in.ndim == 1: xyz_in = xyz_in[np.newaxis, :] # check that these are sensible ECEF values -- their magnitudes need to be # on the order of Earth's radius ecef_magnitudes = np.linalg.norm(xyz_in, axis=1) sensible_radius_range = (6.35e6, 6.39e6) if np.any(ecef_magnitudes <= sensible_radius_range[0]) or np.any( ecef_magnitudes >= sensible_radius_range[1] ): raise ValueError( "ECEF vector magnitudes must be on the order of the radius of the earth" ) xyz_center = XYZ_from_LatLonAlt(latitude, longitude, altitude) xyz_use = np.zeros_like(xyz_in) xyz_use[:, 0] = xyz_in[:, 0] - xyz_center[0] xyz_use[:, 1] = xyz_in[:, 1] - xyz_center[1] xyz_use[:, 2] = xyz_in[:, 2] - xyz_center[2] enu = np.zeros_like(xyz_use) enu[:, 0] = -np.sin(longitude) * xyz_use[:, 0] + np.cos(longitude) * xyz_use[:, 1] enu[:, 1] = ( -np.sin(latitude) * np.cos(longitude) * xyz_use[:, 0] - np.sin(latitude) * np.sin(longitude) * xyz_use[:, 1] + np.cos(latitude) * xyz_use[:, 2] ) enu[:, 2] = ( np.cos(latitude) * np.cos(longitude) * xyz_use[:, 0] + np.cos(latitude) * np.sin(longitude) * xyz_use[:, 1] + np.sin(latitude) * xyz_use[:, 2] ) if len(xyz.shape) == 1: enu = np.squeeze(enu) return enu
[docs]def ECEF_from_ENU(enu, latitude, longitude, altitude): """ Calculate ECEF coordinates from local ENU (east, north, up) coordinates. Parameters ---------- enu : ndarray of float numpy array, shape (Npts, 3), with local ENU coordinates. latitude : float Latitude of center of ENU coordinates in radians. longitude : float Longitude of center of ENU coordinates in radians. altitude : float Altitude of center of ENU coordinates in radians. Returns ------- xyz : ndarray of float numpy array, shape (Npts, 3), with ECEF x,y,z coordinates. """ enu = np.array(enu) if enu.ndim > 1 and enu.shape[1] != 3: raise ValueError("The expected shape of the ENU array is (Npts, 3).") enu_use = enu if enu_use.ndim == 1: enu_use = enu_use[np.newaxis, :] xyz = np.zeros_like(enu_use) xyz[:, 0] = ( -np.sin(latitude) * np.cos(longitude) * enu_use[:, 1] - np.sin(longitude) * enu_use[:, 0] + np.cos(latitude) * np.cos(longitude) * enu_use[:, 2] ) xyz[:, 1] = ( -np.sin(latitude) * np.sin(longitude) * enu_use[:, 1] + np.cos(longitude) * enu_use[:, 0] + np.cos(latitude) * np.sin(longitude) * enu_use[:, 2] ) xyz[:, 2] = np.cos(latitude) * enu_use[:, 1] + np.sin(latitude) * enu_use[:, 2] xyz_center = XYZ_from_LatLonAlt(latitude, longitude, altitude) xyz[:, 0] = xyz[:, 0] + xyz_center[0] xyz[:, 1] = xyz[:, 1] + xyz_center[1] xyz[:, 2] = xyz[:, 2] + xyz_center[2] if len(enu.shape) == 1: xyz = np.squeeze(xyz) return xyz
[docs]def phase_uvw(ra, dec, initial_uvw): """ Calculate phased uvws/positions from unphased ones in an icrs or gcrs frame. This code expects input uvws or positions relative to the telescope location in the same frame that ra/dec are in (e.g. icrs or gcrs) and returns phased ones in the same frame. Note that this code is nearly identical to ENU_from_ECEF, except that it uses an arbitrary phasing center rather than a coordinate center. Parameters ---------- ra : float Right ascension of phase center. dec : float Declination of phase center. initial_uvw : ndarray of float Unphased uvws or positions relative to the array center, shape (Nlocs, 3). Returns ------- uvw : ndarray of float uvw array in the same frame as initial_uvws, ra and dec. """ if initial_uvw.ndim == 1: initial_uvw = initial_uvw[np.newaxis, :] uvw = np.zeros_like(initial_uvw) uvw[:, 0] = -np.sin(ra) * initial_uvw[:, 0] + np.cos(ra) * initial_uvw[:, 1] uvw[:, 1] = ( -np.sin(dec) * np.cos(ra) * initial_uvw[:, 0] - np.sin(dec) * np.sin(ra) * initial_uvw[:, 1] + np.cos(dec) * initial_uvw[:, 2] ) uvw[:, 2] = ( np.cos(dec) * np.cos(ra) * initial_uvw[:, 0] + np.cos(dec) * np.sin(ra) * initial_uvw[:, 1] + np.sin(dec) * initial_uvw[:, 2] ) return uvw
[docs]def unphase_uvw(ra, dec, uvw): """ Calculate unphased uvws/positions from phased ones in an icrs or gcrs frame. This code expects phased uvws or positions in the same frame that ra/dec are in (e.g. icrs or gcrs) and returns unphased ones in the same frame. Parameters ---------- ra : float Right ascension of phase center. dec : float Declination of phase center. uvw : ndarray of float Phased uvws or positions relative to the array center, shape (Nlocs, 3). Returns ------- unphased_uvws : ndarray of float Unphased uvws or positions relative to the array center, shape (Nlocs, 3). """ if uvw.ndim == 1: uvw = uvw[np.newaxis, :] unphased_uvws = np.zeros_like(uvw) unphased_uvws[:, 0] = ( -np.sin(ra) * uvw[:, 0] - np.sin(dec) * np.cos(ra) * uvw[:, 1] + np.cos(dec) * np.cos(ra) * uvw[:, 2] ) unphased_uvws[:, 1] = ( np.cos(ra) * uvw[:, 0] - np.sin(dec) * np.sin(ra) * uvw[:, 1] + np.cos(dec) * np.sin(ra) * uvw[:, 2] ) unphased_uvws[:, 2] = np.cos(dec) * uvw[:, 1] + np.sin(dec) * uvw[:, 2] return unphased_uvws
[docs]def get_lst_for_time(jd_array, latitude, longitude, altitude): """ Get the lsts for a set of jd times at an earth location. Parameters ---------- jd_array : ndarray of float JD times to get lsts for. latitude : float Latitude of location to get lst for in degrees. longitude : float Longitude of location to get lst for in degrees. altitude : float Altitude of location to get lst for in meters. Returns ------- ndarray of float LSTs in radians corresponding to the jd_array. """ lst_array = np.zeros_like(jd_array) for ind, jd in enumerate(np.unique(jd_array)): t = Time( jd, format="jd", location=(Angle(longitude, unit="deg"), Angle(latitude, unit="deg")), ) # avoid errors if iers.conf.auto_max_age is set to None, as we do in # testing if the iers url is down if iers.conf.auto_max_age is None: # pragma: no cover delta, status = t.get_delta_ut1_utc(return_status=True) if status in (iers.TIME_BEFORE_IERS_RANGE, iers.TIME_BEYOND_IERS_RANGE): warnings.warn( "time is out of IERS range, setting delta ut1 utc to " "extrapolated value" ) t.delta_ut1_utc = delta lst_array[ np.where(np.isclose(jd, jd_array, atol=1e-6, rtol=1e-12)) ] = t.sidereal_time("apparent").radian return lst_array
[docs]def get_baseline_redundancies(baselines, baseline_vecs, tol=1.0, with_conjugates=False): """ Find redundant baseline groups. Parameters ---------- baselines : array_like of int Baseline numbers, shape (Nbls,) baseline_vecs : array_like of float Baseline vectors in meters, shape shape (Nbls, 3) tol : float Absolute tolerance of redundancy, in meters. with_conjugates : bool Option to include baselines that are redundant when flipped. Returns ------- baseline_groups : list of lists of int list of lists of redundant baseline numbers vec_bin_centers : list of array_like of float List of vectors describing redundant group centers lengths : list of float List of redundant group baseline lengths in meters baseline_ind_conj : list of int List of baselines that are redundant when reversed. Only returned if with_conjugates is True """ Nbls = baselines.shape[0] if not baseline_vecs.shape == (Nbls, 3): raise ValueError("Baseline vectors must be shape (Nbls, 3)") baseline_vecs = copy.copy(baseline_vecs) # Protect the vectors passed in. if with_conjugates: conjugates = [] for bv in baseline_vecs: uneg = bv[0] < -tol uzer = np.isclose(bv[0], 0.0, atol=tol) vneg = bv[1] < -tol vzer = np.isclose(bv[1], 0.0, atol=tol) wneg = bv[2] < -tol conjugates.append(uneg or (uzer and vneg) or (uzer and vzer and wneg)) conjugates = np.array(conjugates, dtype=bool) baseline_vecs[conjugates] *= -1 baseline_ind_conj = baselines[conjugates] bl_gps, vec_bin_centers, lens = get_baseline_redundancies( baselines, baseline_vecs, tol=tol, with_conjugates=False ) return bl_gps, vec_bin_centers, lens, baseline_ind_conj # For each baseline, list all others that are within the tolerance distance. adj_triu_mat = pdist(baseline_vecs) < tol adj = {} # Adjacency dictionary for bi, col in enumerate(squareform(adj_triu_mat)): col[bi] = True adj[baselines[bi]] = baselines[col] # The adjacency list defines a set of graph edges. # For each baseline b0, loop over its adjacency list ai \in adj[b0] # If adj[b0] is a subset of adj[ai], then ai is in a redundant group with b0 bl_gps = [] for k in adj.keys(): a0 = adj[k] group = [k] for a in a0: if set(a0).issubset(adj[a]) and a not in group: group.append(a) group.sort() bl_gps.append(group) # Groups can be different lengths, but we need to take a unique over an axis # to properly identify unique groups # Pad out all the sub-lists to be the same length pad = len(max(bl_gps, key=len)) bl_gps = np.array([i + [-1] * (pad - len(i)) for i in bl_gps]) # We end up with multiple copies of each redundant group, so remove duplicates bl_gps = np.unique(bl_gps, axis=0).tolist() # remove the dummy pad baselines from each list bl_gps = [[bl for bl in gp if bl != -1] for gp in bl_gps] n_unique = len(bl_gps) vec_bin_centers = np.zeros((n_unique, 3)) for gi, gp in enumerate(bl_gps): inds = [np.where(i == baselines)[0] for i in gp] vec_bin_centers[gi] = np.mean(baseline_vecs[inds, :], axis=0) lens = np.sqrt(np.sum(vec_bin_centers ** 2, axis=1)) if np.sum([len(bg) for bg in bl_gps]) > Nbls: raise ValueError( "Some baselines are falling into multiple" " redundant groups. Lower the tolerance to resolve ambiguity." ) return bl_gps, vec_bin_centers, lens
[docs]def get_antenna_redundancies( antenna_numbers, antenna_positions, tol=1.0, include_autos=False ): """ Find redundant baseline groups based on antenna positions. Parameters ---------- antenna_numbers : array_like of int Antenna numbers, shape (Nants,). antenna_positions : array_like of float Antenna position vectors in the ENU (topocentric) frame in meters, shape (Nants, 3). tol : float Redundancy tolerance in meters. include_autos : bool Option to include autocorrelations. Returns ------- baseline_groups : list of lists of int list of lists of redundant baseline numbers vec_bin_centers : list of array_like of float List of vectors describing redundant group centers lengths : list of float List of redundant group baseline lengths in meters Notes ----- The baseline numbers refer to antenna pairs (a1, a2) such that the baseline vector formed from ENU antenna positions, blvec = enu[a1] - enu[a2] is close to the other baselines in the group. This is achieved by putting baselines in a form of the u>0 convention, but with a tolerance in defining the signs of vector components. To guarantee that the same baseline numbers are present in a UVData object, ``UVData.conjugate_bls('u>0', uvw_tol=tol)``, where `tol` is the tolerance used here. """ Nants = antenna_numbers.size bls = [] bl_vecs = [] for aj in range(Nants): mini = aj + 1 if include_autos: mini = aj for ai in range(mini, Nants): anti, antj = antenna_numbers[ai], antenna_numbers[aj] bidx = antnums_to_baseline(antj, anti, Nants) bv = antenna_positions[ai] - antenna_positions[aj] bl_vecs.append(bv) bls.append(bidx) bls = np.array(bls) bl_vecs = np.array(bl_vecs) gps, vecs, lens, conjs = get_baseline_redundancies( bls, bl_vecs, tol=tol, with_conjugates=True ) # Flip the baselines in the groups. for gi, gp in enumerate(gps): for bi, bl in enumerate(gp): if bl in conjs: gps[gi][bi] = baseline_index_flip(bl, Nants) return gps, vecs, lens
[docs]def mean_collapse( arr, weights=None, axis=None, return_weights=False, return_weights_square=False ): """ Collapse by averaging data. This is similar to np.average, except it handles infs (by giving them zero weight) and zero weight axes (by forcing result to be inf with zero output weight). Parameters ---------- arr : array Input array to process. weights: ndarray, optional weights for average. If none, will default to equal weight for all non-infinite data. axis : int or tuple, optional Axis or axes to collapse (passed to np.sum). Default is all. return_weights : bool Whether to return sum of weights. return_weights_square: bool Whether to return the sum of the square of the weights. Default is False. """ arr = copy.deepcopy(arr) # avoid changing outside if weights is None: weights = np.ones_like(arr) else: weights = copy.deepcopy(weights) weights = weights * np.logical_not(np.isinf(arr)) arr[np.isinf(arr)] = 0 weight_out = np.sum(weights, axis=axis) if return_weights_square: weights_square = weights ** 2 weights_square_out = np.sum(weights_square, axis=axis) out = np.sum(weights * arr, axis=axis) where = weight_out > 1e-10 out = np.true_divide(out, weight_out, where=where) out = np.where(where, out, np.inf) if return_weights and return_weights_square: return out, weight_out, weights_square_out elif return_weights: return out, weight_out elif return_weights_square: return out, weights_square_out else: return out
[docs]def absmean_collapse( arr, weights=None, axis=None, return_weights=False, return_weights_square=False ): """ Collapse by averaging absolute value of data. Parameters ---------- arr : array Input array to process. weights: ndarray, optional weights for average. If none, will default to equal weight for all non-infinite data. axis : int or tuple, optional Axis or axes to collapse (passed to np.sum). Default is all. return_weights : bool Whether to return sum of weights. return_weights_square: bool whether to return the sum of the squares of the weights. Default is False. """ return mean_collapse( np.abs(arr), weights=weights, axis=axis, return_weights=return_weights, return_weights_square=return_weights_square, )
[docs]def quadmean_collapse( arr, weights=None, axis=None, return_weights=False, return_weights_square=False ): """ Collapse by averaging in quadrature. Parameters ---------- arr : array Input array to process. weights: ndarray, optional weights for average. If none, will default to equal weight for all non-infinite data. axis : int or tuple, optional Axis or axes to collapse (passed to np.sum). Default is all. return_weights : bool Whether to return sum of weights. return_weights_square: bool whether to return the sum of the squares of the weights. Default is False. """ out = mean_collapse( np.abs(arr) ** 2, weights=weights, axis=axis, return_weights=return_weights, return_weights_square=return_weights_square, ) if return_weights and return_weights_square: return np.sqrt(out[0]), out[1], out[2] elif return_weights or return_weights_square: return np.sqrt(out[0]), out[1] else: return np.sqrt(out)
[docs]def or_collapse( arr, weights=None, axis=None, return_weights=False, return_weights_square=False ): """ Collapse using OR operation. Parameters ---------- arr : array Input array to process. weights: ndarray, optional NOT USED, but kept for symmetry with other collapsing functions. axis : int or tuple, optional Axis or axes to collapse (take OR over). Default is all. return_weights : bool Whether to return dummy weights array. NOTE: the dummy weights will simply be an array of ones return_weights_square: bool NOT USED, but kept for symmetry with other collapsing functions. """ if arr.dtype != np.bool: raise ValueError("Input to or_collapse function must be boolean array") out = np.any(arr, axis=axis) if (weights is not None) and not np.all(weights == weights.reshape(-1)[0]): warnings.warn("Currently weights are not handled when OR-ing boolean arrays.") if return_weights: return out, np.ones_like(out, dtype=np.float) else: return out
[docs]def and_collapse( arr, weights=None, axis=None, return_weights=False, return_weights_square=False ): """ Collapse using AND operation. Parameters ---------- arr : array Input array to process. weights: ndarray, optional NOT USED, but kept for symmetry with other collapsing functions. axis : int or tuple, optional Axis or axes to collapse (take AND over). Default is all. return_weights : bool Whether to return dummy weights array. NOTE: the dummy weights will simply be an array of ones return_weights_square: bool NOT USED, but kept for symmetry with other collapsing functions. """ if arr.dtype != np.bool: raise ValueError("Input to and_collapse function must be boolean array") out = np.all(arr, axis=axis) if (weights is not None) and not np.all(weights == weights.reshape(-1)[0]): warnings.warn("Currently weights are not handled when AND-ing boolean arrays.") if return_weights: return out, np.ones_like(out, dtype=np.float) else: return out
[docs]def collapse( arr, alg, weights=None, axis=None, return_weights=False, return_weights_square=False ): """ Parent function to collapse an array with a given algorithm. Parameters ---------- arr : array Input array to process. alg : str Algorithm to use. Must be defined in this function with corresponding subfunction above. weights: ndarray, optional weights for collapse operation (e.g. weighted mean). NOTE: Some subfunctions do not use the weights. See corresponding doc strings. axis : int or tuple, optional Axis or axes to collapse. Default is all. return_weights : bool Whether to return sum of weights. return_weights_square: bool Whether to return the sum of the squares of the weights. Default is False. """ collapse_dict = { "mean": mean_collapse, "absmean": absmean_collapse, "quadmean": quadmean_collapse, "or": or_collapse, "and": and_collapse, } try: out = collapse_dict[alg]( arr, weights=weights, axis=axis, return_weights=return_weights, return_weights_square=return_weights_square, ) except KeyError: raise ValueError( "Collapse algorithm must be one of: " + ", ".join(collapse_dict.keys()) + "." ) return out
[docs]def uvcalibrate( uvdata, uvcal, inplace=True, prop_flags=True, flag_missing=True, Dterm_cal=False, delay_convention="minus", undo=False, ): """ Calibrate a UVData object with a UVCal object. Parameters ---------- uvdata : UVData object UVData object to calibrate. uvcal : UVCal object UVCal object containing the calibration. inplace : bool, optional if True edit uvdata in place, else deepcopy prop_flags : bool, optional if True, propagate calibration flags to data flags and doesn't use flagged gains. Otherwise, uses flagged gains and does not propagate calibration flags to data flags. flag_missing : bool, optional if True, flag baselines in uvdata if a participating antenna or polarization is missing in uvcal. Dterm_cal : bool, optional Calibrate the off-diagonal terms in the Jones matrix if present in uvcal. Default is False. Currently not implemented. delay_convention : str, optional Exponent sign to use in conversion of 'delay' to 'gain' cal_type if the input uvcal is not inherently 'gain' cal_type. Default to 'minus'. undo : bool, optional If True, undo the provided calibration. i.e. apply the calibration with flipped gain_convention. Flag propagation rules apply the same. Returns ------- UVData, optional Returns if not inplace """ # deepcopy for not inplace if not inplace: uvdata = copy.deepcopy(uvdata) # input checks if uvcal.cal_type == "delay": # make a copy that is converted to gain uvcal = copy.deepcopy(uvcal) uvcal.convert_to_gain(delay_convention=delay_convention) # D-term calibration if Dterm_cal: # check for D-terms if -7 not in uvcal.jones_array and -8 not in uvcal.jones_array: raise ValueError( "Cannot apply D-term calibration without -7 or -8" "Jones polarization in uvcal object." ) raise NotImplementedError("D-term calibration is not yet implemented.") # No D-term calibration else: # iterate over keys for key in uvdata.get_antpairpols(): # get indices for this key blt_inds = uvdata.antpair2ind(key) pol_ind = np.argmin( np.abs( uvdata.polarization_array - polstr2num(key[2], uvdata.x_orientation) ) ) # try to get gains for each antenna ant1 = (key[0], key[2][0]) ant2 = (key[1], key[2][1]) if not uvcal._has_key(*ant1) or not uvcal._has_key(*ant2): if flag_missing: uvdata.flag_array[blt_inds, 0, :, pol_ind] = True continue gain = ( uvcal.get_gains(ant1) * np.conj(uvcal.get_gains(ant2)) ).T # tranpose to match uvdata shape flag = (uvcal.get_flags(ant1) | uvcal.get_flags(ant2)).T # propagate flags if prop_flags: mask = np.isclose(gain, 0.0) | flag gain[mask] = 1.0 uvdata.flag_array[blt_inds, 0, :, pol_ind] += mask # apply to data mult_gains = uvcal.gain_convention == "multiply" if undo: mult_gains = not mult_gains if mult_gains: uvdata.data_array[blt_inds, 0, :, pol_ind] *= gain else: uvdata.data_array[blt_inds, 0, :, pol_ind] /= gain # update attributes uvdata.history += "\nCalibrated with pyuvdata.utils.uvcalibrate." if undo: uvdata.vis_units = "UNCALIB" else: if uvcal.gain_scale is not None: uvdata.vis_units = uvcal.gain_scale if not inplace: return uvdata
[docs]def apply_uvflag( uvd, uvf, inplace=True, unflag_first=False, flag_missing=True, force_pol=True ): """ Apply flags from a UVFlag to a UVData instantiation. Note that if uvf.Nfreqs or uvf.Ntimes is 1, it will broadcast flags across that axis. Parameters ---------- uvd : UVData object UVData object to add flags to. uvf : UVFlag object A UVFlag object in flag mode. inplace : bool If True overwrite flags in uvd, otherwise return new object unflag_first : bool If True, completely unflag the UVData before applying flags. Else, OR the inherent uvd flags with uvf flags. flag_missing : bool If input uvf is a baseline type and antpairs in uvd do not exist in uvf, flag them in uvd. Otherwise leave them untouched. force_pol : bool If True, broadcast flags to all polarizations if they do not match. Only works if uvf.Npols == 1. Returns ------- UVData If not inplace, returns new UVData object with flags applied """ # assertions if uvf.mode != "flag": raise ValueError("UVFlag must be flag mode") if not inplace: uvd = copy.deepcopy(uvd) # make a deepcopy by default b/c it is generally edited inplace downstream uvf = copy.deepcopy(uvf) # convert to baseline type if uvf.type != "baseline": # edits inplace uvf.to_baseline(uvd, force_pol=force_pol) else: # make sure polarizations match or force_pol uvd_pols, uvf_pols = ( uvd.polarization_array.tolist(), uvf.polarization_array.tolist(), ) if set(uvd_pols) != set(uvf_pols): if uvf.Npols == 1 and force_pol: # if uvf is 1pol we can make them match: also edits inplace uvf.polarization_array = uvd.polarization_array uvf.Npols = len(uvf.polarization_array) uvf_pols = uvf.polarization_array.tolist() else: raise ValueError("Input uvf and uvd polarizations do not match") # make sure polarization ordering is correct: also edits inplace uvf.polarization_array = uvf.polarization_array[ [uvd_pols.index(pol) for pol in uvf_pols] ] # check time and freq shapes match: if Ntimes or Nfreqs is 1, allow # implicit broadcasting if uvf.Ntimes == 1: mismatch_times = False elif uvf.Ntimes == uvd.Ntimes: tdiff = np.unique(uvf.time_array) - np.unique(uvd.time_array) mismatch_times = np.any(tdiff > np.max(np.abs(uvf._time_array.tols))) else: mismatch_times = True if mismatch_times: raise ValueError("UVFlag and UVData have mismatched time arrays.") if uvf.Nfreqs == 1: mismatch_freqs = False elif uvf.Nfreqs == uvd.Nfreqs: fdiff = np.unique(uvf.freq_array) - np.unique(uvd.freq_array) mismatch_freqs = np.any(fdiff > np.max(np.abs(uvf._freq_array.tols))) else: mismatch_freqs = True if mismatch_freqs: raise ValueError("UVFlag and UVData have mismatched frequency arrays.") # unflag if desired if unflag_first: uvd.flag_array[:] = False # iterate over antpairs and apply flags: TODO need to be able to handle # conjugated antpairs uvf_antpairs = uvf.get_antpairs() for ap in uvd.get_antpairs(): uvd_ap_inds = uvd.antpair2ind(ap) if ap not in uvf_antpairs: if flag_missing: uvd.flag_array[uvd_ap_inds] = True continue uvf_ap_inds = uvf.antpair2ind(*ap) # addition of boolean is OR uvd.flag_array[uvd_ap_inds] += uvf.flag_array[uvf_ap_inds] uvd.history += "\nFlagged with pyuvdata.utils.apply_uvflags." if not inplace: return uvd