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1import os 

2import numpy as np 

3import healpy as hp 

4from lsst.utils import getPackageDir 

5from lsst.sims.maf.utils import radec2pix 

6from . import BaseMap 

7 

8__all__ = ['StellarDensityMap'] 

9 

10class StellarDensityMap(BaseMap): 

11 """ 

12 Return the cumulative stellar luminosity function for each slicepoint. Units of stars per sq degree. 

13 Uses a healpix map of nside=64. Uses the nearest healpix point for other ra,dec values. 

14 

15 Parameters 

16 ---------- 

17 startype : str ('allstars', 'wdstars') 

18 Load the luminosity function for all stars ('allstars'), which includes main-sequence stars 

19 white dwarfs, blue horozontal branch, RR Lyrae, and Cepheids. The 'wdstars' option only includes 

20 white dwarf stars. 

21 filtername : str 

22 Filter to use. Options of u,g,r,i,z,y 

23 """ 

24 def __init__(self, startype='allstars', filtername='r'): 

25 self.mapDir = os.path.join(getPackageDir('sims_maps'), 'StarMaps') 

26 self.filtername = filtername 

27 if startype == 'allstars': 

28 self.startype = '' 

29 else: 

30 self.startype = startype+'_' 

31 

32 def _readMap(self): 

33 filename = 'starDensity_%s_%snside_64.npz' % (self.filtername, self.startype) 

34 starMap = np.load(os.path.join(self.mapDir,filename)) 

35 self.starMap = starMap['starDensity'].copy() 

36 self.starMapBins = starMap['bins'].copy() 

37 self.starmapNside = hp.npix2nside(np.size(self.starMap[:,0])) 

38 

39 def run(self, slicePoints): 

40 self._readMap() 

41 

42 nsideMatch = False 

43 if 'nside' in slicePoints: 

44 if slicePoints['nside'] == self.starmapNside: 

45 slicePoints[f'starLumFunc_{self.filtername}'] = self.starMap 

46 nsideMatch = True 

47 if not nsideMatch: 

48 # Compute the healpix for each slicepoint on the nside=64 grid 

49 indx = radec2pix(self.starmapNside, slicePoints['ra'], slicePoints['dec']) 

50 slicePoints[f'starLumFunc_{self.filtername}'] = self.starMap[indx,:] 

51 

52 slicePoints[f'starMapBins_{self.filtername}'] = self.starMapBins 

53 return slicePoints