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import warnings 

import numpy as np 

import palpy 

from lsst.sims.utils import Site, m5_flat_sed, xyz_from_ra_dec, xyz_angular_radius, \ 

_buildTree, _xyz_from_ra_dec 

from lsst.sims.survey.fields import FieldsDatabase 

from .baseStacker import BaseStacker 

 

__all__ = ['NormAirmassStacker', 'ParallaxFactorStacker', 'HourAngleStacker', 

'FilterColorStacker', 'ZenithDistStacker', 'ParallacticAngleStacker', 

'SeasonStacker', 'DcrStacker', 'FiveSigmaStacker', 'OpSimFieldStacker'] 

 

# Original stackers by Peter Yoachim (yoachim@uw.edu) 

# Filter color stacker by Lynne Jones (lynnej@uw.edu) 

# Season stacker by Phil Marshall (dr.phil.marshall@gmail.com), 

# modified by Humna Awan (humna.awan@rutgers.edu) 

 

 

class FiveSigmaStacker(BaseStacker): 

""" 

Calculate the 5-sigma limiting depth for a point source in the given conditions. 

 

This is generally not needed, unless the m5 parameters have been updated 

or m5 was not previously calculated. 

""" 

colsAdded = ['m5_simsUtils'] 

 

def __init__(self, airmassCol='airmass', seeingCol='seeingFwhmEff', skybrightnessCol='skyBrightness', 

filterCol='filter', exptimeCol='visitExposureTime'): 

self.units = ['mag'] 

self.colsReq = [airmassCol, seeingCol, skybrightnessCol, filterCol, exptimeCol] 

self.airmassCol = airmassCol 

self.seeingCol = seeingCol 

self.skybrightnessCol = skybrightnessCol 

self.filterCol = filterCol 

self.exptimeCol = exptimeCol 

 

def _run(self, simData, cols_present=False): 

if cols_present: 

# Column already present in data; assume it needs updating and recalculate. 

return simData 

filts = np.unique(simData[self.filterCol]) 

for filtername in filts: 

infilt = np.where(simData[self.filterCol] == filtername) 

simData['m5_simsUtils'][infilt] = m5_flat_sed(filtername, 

simData[infilt][self.skybrightnessCol], 

simData[infilt][self.seeingCol], 

simData[infilt][self.exptimeCol], 

simData[infilt][self.airmassCol]) 

return simData 

 

 

class NormAirmassStacker(BaseStacker): 

"""Calculate the normalized airmass for each opsim pointing. 

""" 

colsAdded = ['normairmass'] 

 

def __init__(self, airmassCol='airmass', decCol='fieldDec', 

degrees=True, telescope_lat = -30.2446388): 

self.units = ['X / Xmin'] 

self.colsReq = [airmassCol, decCol] 

self.airmassCol = airmassCol 

self.decCol = decCol 

self.telescope_lat = telescope_lat 

self.degrees = degrees 

 

def _run(self, simData, cols_present=False): 

"""Calculate new column for normalized airmass.""" 

# Run method is required to calculate column. 

# Driver runs getColInfo to know what columns are needed from db & which are calculated, 

# then gets data from db and then calculates additional columns (via run methods here). 

72 ↛ 74line 72 didn't jump to line 74, because the condition on line 72 was never true if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

dec = simData[self.decCol] 

76 ↛ 78line 76 didn't jump to line 78, because the condition on line 76 was never false if self.degrees: 

dec = np.radians(dec) 

min_z_possible = np.abs(dec - np.radians(self.telescope_lat)) 

min_airmass_possible = 1./np.cos(min_z_possible) 

simData['normairmass'] = simData[self.airmassCol] / min_airmass_possible 

return simData 

 

 

class ZenithDistStacker(BaseStacker): 

"""Calculate the zenith distance for each pointing. 

If 'degrees' is True, then assumes altCol is in degrees and returns degrees. 

If 'degrees' is False, assumes altCol is in radians and returns radians. 

""" 

colsAdded = ['zenithDistance'] 

 

def __init__(self, altCol='altitude', degrees=True): 

self.altCol = altCol 

self.degrees = degrees 

94 ↛ 97line 94 didn't jump to line 97, because the condition on line 94 was never false if self.degrees: 

self.units = ['degrees'] 

else: 

self.unit = ['radians'] 

self.colsReq = [self.altCol] 

 

def _run(self, simData, cols_present=False): 

"""Calculate new column for zenith distance.""" 

if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

if self.degrees: 

simData['zenithDistance'] = 90.0 - simData[self.altCol] 

else: 

simData['zenithDistance'] = np.pi/2.0 - simData[self.altCol] 

return simData 

 

 

class ParallaxFactorStacker(BaseStacker): 

"""Calculate the parallax factors for each opsim pointing. Output parallax factor in arcseconds. 

""" 

colsAdded = ['ra_pi_amp', 'dec_pi_amp'] 

 

def __init__(self, raCol='fieldRA', decCol='fieldDec', dateCol='observationStartMJD', degrees=True): 

self.raCol = raCol 

self.decCol = decCol 

self.dateCol = dateCol 

self.units = ['arcsec', 'arcsec'] 

self.colsReq = [raCol, decCol, dateCol] 

self.degrees = degrees 

 

def _gnomonic_project_toxy(self, RA1, Dec1, RAcen, Deccen): 

"""Calculate x/y projection of RA1/Dec1 in system with center at RAcen, Deccenp. 

Input radians. 

""" 

# also used in Global Telescope Network website 

cosc = np.sin(Deccen) * np.sin(Dec1) + np.cos(Deccen) * np.cos(Dec1) * np.cos(RA1-RAcen) 

x = np.cos(Dec1) * np.sin(RA1-RAcen) / cosc 

y = (np.cos(Deccen)*np.sin(Dec1) - np.sin(Deccen)*np.cos(Dec1)*np.cos(RA1-RAcen)) / cosc 

return x, y 

 

def _run(self, simData, cols_present=False): 

136 ↛ 138line 136 didn't jump to line 138, because the condition on line 136 was never true if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

ra_pi_amp = np.zeros(np.size(simData), dtype=[('ra_pi_amp', 'float')]) 

dec_pi_amp = np.zeros(np.size(simData), dtype=[('dec_pi_amp', 'float')]) 

ra_geo1 = np.zeros(np.size(simData), dtype='float') 

dec_geo1 = np.zeros(np.size(simData), dtype='float') 

ra_geo = np.zeros(np.size(simData), dtype='float') 

dec_geo = np.zeros(np.size(simData), dtype='float') 

ra = simData[self.raCol] 

dec = simData[self.decCol] 

147 ↛ 151line 147 didn't jump to line 151, because the condition on line 147 was never false if self.degrees: 

ra = np.radians(ra) 

dec = np.radians(dec) 

 

for i, ack in enumerate(simData): 

mtoa_params = palpy.mappa(2000., simData[self.dateCol][i]) 

# Object with a 1 arcsec parallax 

ra_geo1[i], dec_geo1[i] = palpy.mapqk(ra[i], dec[i], 

0., 0., 1., 0., mtoa_params) 

# Object with no parallax 

ra_geo[i], dec_geo[i] = palpy.mapqk(ra[i], dec[i], 

0., 0., 0., 0., mtoa_params) 

x_geo1, y_geo1 = self._gnomonic_project_toxy(ra_geo1, dec_geo1, 

ra, dec) 

x_geo, y_geo = self._gnomonic_project_toxy(ra_geo, dec_geo, ra, dec) 

# Return ra_pi_amp and dec_pi_amp in arcseconds. 

ra_pi_amp[:] = np.degrees(x_geo1-x_geo)*3600. 

dec_pi_amp[:] = np.degrees(y_geo1-y_geo)*3600. 

simData['ra_pi_amp'] = ra_pi_amp 

simData['dec_pi_amp'] = dec_pi_amp 

return simData 

 

 

class DcrStacker(BaseStacker): 

"""Calculate the RA,Dec offset expected for an object due to differential chromatic refraction. 

 

For DCR calculation, we also need zenithDistance, HA, and PA -- but these will be explicitly 

handled within this stacker so that setup is consistent and they run in order. If those values 

have already been calculated elsewhere, they will not be overwritten. 

 

Parameters 

---------- 

filterCol : str 

The name of the column with filter names. Default 'fitler'. 

altCol : str 

Name of the column with altitude info. Default 'altitude'. 

raCol : str 

Name of the column with RA. Default 'fieldRA'. 

decCol : str 

Name of the column with Dec. Default 'fieldDec'. 

lstCol : str 

Name of the column with local sidereal time. Default 'observationStartLST'. 

site : str or lsst.sims.utils.Site 

Name of the observory or a lsst.sims.utils.Site object. Default 'LSST'. 

mjdCol : str 

Name of column with modified julian date. Default 'observationStartMJD' 

dcr_magnitudes : dict 

Magitude of the DCR offset for each filter at altitude/zenith distance of 45 degrees. 

Defaults u=0.07, g=0.07, r=0.50, i=0.045, z=0.042, y=0.04 (all arcseconds). 

 

Returns 

------- 

numpy.array 

Returns array with additional columns 'ra_dcr_amp' and 'dec_dcr_amp' with the DCR offsets 

for each observation. Also runs ZenithDistStacker and ParallacticAngleStacker. 

""" 

colsAdded = ['ra_dcr_amp', 'dec_dcr_amp'] # zenithDist, HA, PA 

 

def __init__(self, filterCol='filter', altCol='altitude', degrees=True, 

raCol='fieldRA', decCol='fieldDec', lstCol='observationStartLST', 

site='LSST', mjdCol='observationStartMJD', 

dcr_magnitudes=None): 

self.units = ['arcsec', 'arcsec'] 

210 ↛ 214line 210 didn't jump to line 214, because the condition on line 210 was never false if dcr_magnitudes is None: 

# DCR amplitudes are in arcseconds. 

self.dcr_magnitudes = {'u': 0.07, 'g': 0.07, 'r': 0.050, 'i': 0.045, 'z': 0.042, 'y': 0.04} 

else: 

self.dcr_magnitudes = dcr_magnitudes 

self.zdCol = 'zenithDistance' 

self.paCol = 'PA' 

self.filterCol = filterCol 

self.raCol = raCol 

self.decCol = decCol 

self.degrees = degrees 

self.colsReq = [filterCol, raCol, decCol, altCol, lstCol] 

# 'zenithDist', 'PA', 'HA' are additional columns required, coming from other stackers which must 

# also be configured -- so we handle this explicitly here. 

self.zstacker = ZenithDistStacker(altCol=altCol, degrees=self.degrees) 

self.pastacker = ParallacticAngleStacker(raCol=raCol, decCol=decCol, mjdCol=mjdCol, 

degrees=self.degrees, 

lstCol=lstCol, site=site) 

# Note that RA/Dec could be coming from a dither stacker! 

# But we will assume that coord stackers will be handled separately. 

 

 

def _run(self, simData, cols_present=False): 

if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

# Need to make sure the Zenith stacker gets run first 

# Call _run method because already added these columns due to 'colsAdded' line. 

simData = self.zstacker.run(simData) 

simData = self.pastacker.run(simData) 

if self.degrees: 

zenithTan = np.tan(np.radians(simData[self.zdCol])) 

parallacticAngle = np.radians(simData[self.paCol]) 

else: 

zenithTan = np.tan(simData[self.zdCol]) 

parallacticAngle = simData[self.paCol] 

dcr_in_ra = zenithTan * np.sin(parallacticAngle) 

dcr_in_dec = zenithTan * np.cos(parallacticAngle) 

for filtername in np.unique(simData[self.filterCol]): 

fmatch = np.where(simData[self.filterCol] == filtername) 

dcr_in_ra[fmatch] = self.dcr_magnitudes[filtername] * dcr_in_ra[fmatch] 

dcr_in_dec[fmatch] = self.dcr_magnitudes[filtername] * dcr_in_dec[fmatch] 

simData['ra_dcr_amp'] = dcr_in_ra 

simData['dec_dcr_amp'] = dcr_in_dec 

return simData 

 

 

class HourAngleStacker(BaseStacker): 

"""Add the Hour Angle for each observation. 

Always in HOURS. 

""" 

colsAdded = ['HA'] 

 

def __init__(self, lstCol='observationStartLST', raCol='fieldRA', degrees=True): 

self.units = ['Hours'] 

self.colsReq = [lstCol, raCol] 

self.lstCol = lstCol 

self.raCol = raCol 

self.degrees = degrees 

 

def _run(self, simData, cols_present=False): 

"""HA = LST - RA """ 

272 ↛ 274line 272 didn't jump to line 274, because the condition on line 272 was never true if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

275 ↛ 276line 275 didn't jump to line 276, because the condition on line 275 was never true if len(simData) == 0: 

return simData 

277 ↛ 281line 277 didn't jump to line 281, because the condition on line 277 was never false if self.degrees: 

ra = np.radians(simData[self.raCol]) 

lst = np.radians(simData[self.lstCol]) 

else: 

ra = simData[self.raCol] 

lst = simData[self.lstCol] 

# Check that LST is reasonable 

284 ↛ 285line 284 didn't jump to line 285, because the condition on line 284 was never true if (np.min(lst) < 0) | (np.max(lst) > 2.*np.pi): 

warnings.warn('LST values are not between 0 and 2 pi') 

# Check that RA is reasonable 

287 ↛ 288line 287 didn't jump to line 288, because the condition on line 287 was never true if (np.min(ra) < 0) | (np.max(ra) > 2.*np.pi): 

warnings.warn('RA values are not between 0 and 2 pi') 

ha = lst - ra 

# Wrap the results so HA between -pi and pi 

ha = np.where(ha < -np.pi, ha + 2. * np.pi, ha) 

ha = np.where(ha > np.pi, ha - 2. * np.pi, ha) 

# Convert radians to hours 

simData['HA'] = ha*12/np.pi 

return simData 

 

 

class ParallacticAngleStacker(BaseStacker): 

"""Add the parallactic angle to each visit. 

If 'degrees' is True, this will be in degrees (as are all other angles). If False, then in radians. 

""" 

colsAdded = ['PA'] 

 

def __init__(self, raCol='fieldRA', decCol='fieldDec', degrees=True, mjdCol='observationStartMJD', 

lstCol='observationStartLST', site='LSST'): 

 

self.lstCol = lstCol 

self.raCol = raCol 

self.decCol = decCol 

self.degrees = degrees 

self.mjdCol = mjdCol 

self.site = Site(name=site) 

self.units = ['radians'] 

self.colsReq = [self.raCol, self.decCol, self.mjdCol, self.lstCol] 

self.haStacker = HourAngleStacker(lstCol=lstCol, raCol=raCol, degrees=self.degrees) 

 

def _run(self, simData, cols_present=False): 

# Equation from: 

# http://www.gb.nrao.edu/~rcreager/GBTMetrology/140ft/l0058/gbtmemo52/memo52.html 

# or 

# http://www.gb.nrao.edu/GBT/DA/gbtidl/release2pt9/contrib/contrib/parangle.pro 

322 ↛ 324line 322 didn't jump to line 324, because the condition on line 322 was never true if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

# Using the run method (not _run) means that if HA is present, it will not be recalculated. 

simData = self.haStacker.run(simData) 

327 ↛ 330line 327 didn't jump to line 330, because the condition on line 327 was never false if self.degrees: 

dec = np.radians(simData[self.decCol]) 

else: 

dec = simData[self.decCol] 

simData['PA'] = np.arctan2(np.sin(simData['HA']*np.pi/12.), (np.cos(dec) * 

np.tan(self.site.latitude_rad) - np.sin(dec) * 

np.cos(simData['HA']*np.pi/12.))) 

334 ↛ 336line 334 didn't jump to line 336, because the condition on line 334 was never false if self.degrees: 

simData['PA'] = np.degrees(simData['PA']) 

return simData 

 

 

class FilterColorStacker(BaseStacker): 

"""Translate filters ('u', 'g', 'r' ..) into RGB tuples. 

""" 

colsAdded = ['rRGB', 'gRGB', 'bRGB'] 

 

def __init__(self, filterCol='filter'): 

self.filter_rgb_map = {'u': (0, 0, 1), # dark blue 

'g': (0, 1, 1), # cyan 

'r': (0, 1, 0), # green 

'i': (1, 0.5, 0.3), # orange 

'z': (1, 0, 0), # red 

'y': (1, 0, 1)} # magenta 

self.filterCol = filterCol 

# self.units used for plot labels 

self.units = ['rChan', 'gChan', 'bChan'] 

# Values required for framework operation: this specifies the data columns required from the database. 

self.colsReq = [self.filterCol] 

 

def _run(self, simData, cols_present=False): 

# Translate filter names into numbers. 

if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

filtersUsed = np.unique(simData[self.filterCol]) 

for f in filtersUsed: 

if f not in self.filter_rgb_map: 

raise IndexError('Filter %s not in filter_rgb_map' % (f)) 

match = np.where(simData[self.filterCol] == f)[0] 

simData['rRGB'][match] = self.filter_rgb_map[f][0] 

simData['gRGB'][match] = self.filter_rgb_map[f][1] 

simData['bRGB'][match] = self.filter_rgb_map[f][2] 

return simData 

 

 

class SeasonStacker(BaseStacker): 

"""Add an integer label to show which season a given visit is in. 

 

The season only depends on the RA of the object: we compute the MJD 

when each object is on the meridian at midnight, and subtract 6 

months to get the start date of each season. 

The season index range is 0-10. 

Must wrap 0th and 10th to get a total of 10 seasons. 

""" 

colsAdded = ['year', 'season'] 

 

def __init__(self, mjdCol='observationStartMJD', RACol='fieldRA', degrees=True): 

# Names of columns we need from database. 

self.colsReq = [mjdCol, RACol] 

# List of units for our new columns. 

self.units = ['yr', ''] 

# And save the column names. 

self.mjdCol = mjdCol 

self.RACol = RACol 

self.degrees = degrees 

 

def _run(self, simData, cols_present=False): 

if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

# Define year number: (note that opsim defines "years" in flat 365 days). 

year = np.floor((simData[self.mjdCol] - simData[self.mjdCol][0]) / 365) 

# Convert RA to Hours 

if self.degrees: 

objRA = simData[self.RACol]/15.0 

else: 

objRA = np.degrees(simData[self.RACol])/15.0 

# objRA=0 on autumnal equinox. 

# autumnal equinox 2014 happened on Sept 23 --> Equinox MJD 

Equinox = 2456923.5 - 2400000.5 

# Use 365.25 for the length of a year here, because we're dealing with real seasons. 

daysSinceEquinox = 0.5*objRA*(365.25/12.0) # 0.5 to go from RA to month; 365.25/12.0 months to days 

firstSeasonBegan = Equinox + daysSinceEquinox - 0.5*365.25 # in MJD 

# Now we can compute the number of years since the first season 

# began, and so assign a global integer season number: 

globalSeason = np.floor((simData[self.mjdCol] - firstSeasonBegan)/365.25) 

# Subtract off season number of first observation: 

season = globalSeason - np.min(globalSeason) 

simData['year'] = year 

simData['season'] = season 

return simData 

 

 

class OpSimFieldStacker(BaseStacker): 

"""Add the fieldId of the closest OpSim field for each RA/Dec pointing. 

 

Parameters 

---------- 

raCol : str, opt 

Name of the RA column. Default fieldRA. 

decCol : str, opt 

Name of the Dec column. Default fieldDec. 

 

""" 

colsAdded = ['opsimFieldId'] 

 

def __init__(self, raCol='fieldRA', decCol='fieldDec', degrees=True): 

self.colsReq = [raCol, decCol] 

self.units = ['#'] 

self.raCol = raCol 

self.decCol = decCol 

self.degrees = degrees 

fields_db = FieldsDatabase() 

# Returned RA/Dec coordinates in degrees 

fieldid, ra, dec = fields_db.get_id_ra_dec_arrays("select * from Field;") 

asort = np.argsort(fieldid) 

self.tree = _buildTree(np.radians(ra[asort]), 

np.radians(dec[asort])) 

 

def _run(self, simData, cols_present=False): 

448 ↛ 450line 448 didn't jump to line 450, because the condition on line 448 was never true if cols_present: 

# Column already present in data; assume it is correct and does not need recalculating. 

return simData 

 

452 ↛ 454line 452 didn't jump to line 454, because the condition on line 452 was never true if self.degrees: 

# use public method (degrees) 

coord_x, coord_y, coord_z = xyz_from_ra_dec(simData[self.raCol], 

simData[self.decCol]) 

field_ids = self.tree.query_ball_point(list(zip(coord_x, coord_y, coord_z)), xyz_angular_radius()) 

 

else: 

# use private method (radians) 

coord_x, coord_y, coord_z = _xyz_from_ra_dec(simData[self.raCol], 

simData[self.decCol]) 

field_ids = self.tree.query_ball_point(list(zip(coord_x, coord_y, coord_z)), xyz_angular_radius()) 

 

simData['opsimFieldId'] = np.array([ids[0] for ids in field_ids]) + 1 

return simData