fix competing tsnr ensemble caches

py/desispec/tsnr.py

@@ -405,16 +405,12 @@ def write(self,filename) :
         log.info('Successfully written to '+filename)
 
 _tsnr_ensembles = None
-def get_ensemble(dirpath=None, bands=["b","r","z"], smooth=0):
+def get_ensemble(dirpath=None, smooth=0):
     '''
-    Function that takes a frame object and a bitmask and
-    returns ivar (and optionally mask) array(s) that have fibers with
-    offending bits in fibermap['FIBERSTATUS'] set to
-    0 in ivar and optionally flips a bit in mask.
+    Read TSNR ensembles from $DESIMODEL/data/tsnr
 
     Args:
         dirpath: path to the dir. with ensemble dflux files. default is $DESIMODEL/data/tsnr
-        bands (list, optional):  bands to expect, typically [BRZ] - case ignored.
         smooth (int, optional):  Further convolve the residual ensemble flux.
 
     Returns:
@@ -423,17 +419,25 @@ def get_ensemble(dirpath=None, bands=["b","r","z"], smooth=0):
         frequency residual for the ensemble.  See doc. 4723.
     '''
 
+    log = get_logger()
+
     global _tsnr_ensembles
     if _tsnr_ensembles is not None:
+        log.debug('Using cached TSNR ensemble')
         return _tsnr_ensembles
 
+    #- all ensembles have these bands
+    bands = ('b', 'r', 'z')
+
     t0 = time.time()
 
     log=get_logger()
     if dirpath is None :
         dirpath = os.path.join(os.environ["DESIMODEL"],"data/tsnr")
 
-    paths = glob.glob(dirpath + '/tsnr-ensemble-*.fits')
+    log.info('Reading TSNR ensemble files from %s', dirpath)
+
+    paths = sorted(glob.glob(dirpath + '/tsnr-ensemble-*.fits'))
 
     wave = {}
     flux = {}
@@ -445,23 +449,22 @@ def get_ensemble(dirpath=None, bands=["b","r","z"], smooth=0):
 
     for path in paths:
         tracer = path.split('/')[-1].split('-')[2].replace('.fits','')
-        dat    = fits.open(path)
-
-        if 'FLUXSCAL' in dat[0].header :
-            scale_factor = dat[0].header['FLUXSCAL']
-            log.info("for {} apply scale factor = {:4.3f}".format(path,scale_factor))
-        else :
-            scale_factor = 1.
-
-        for band in bands:
-            wave[band] = dat['WAVE_{}'.format(band.upper())].data
-            flux[band] = scale_factor*dat['DFLUX_{}'.format(band.upper())].data
-            ivar[band] = 1.e99 * np.ones_like(flux[band])
-
-            # 125: 100. A in 0.8 pixel.
-            if smooth > 0:
-                flux[band] = convolve(flux[band][0,:], Box1DKernel(smooth), boundary='extend')
-                flux[band] = flux[band].reshape(1, len(flux[band]))
+        with fits.open(path) as dat:
+            if 'FLUXSCAL' in dat[0].header :
+                scale_factor = dat[0].header['FLUXSCAL']
+                log.info("for {} apply scale factor = {:4.3f}".format(path,scale_factor))
+            else :
+                scale_factor = 1.
+
+            for band in bands:
+                wave[band] = dat['WAVE_{}'.format(band.upper())].data
+                flux[band] = scale_factor*dat['DFLUX_{}'.format(band.upper())].data
+                ivar[band] = 1.e99 * np.ones_like(flux[band])
+
+                # 125: 100. A in 0.8 pixel.
+                if smooth > 0:
+                    flux[band] = convolve(flux[band][0,:], Box1DKernel(smooth), boundary='extend')
+                    flux[band] = flux[band].reshape(1, len(flux[band]))
 
         ensembles[tracer] = Spectra(bands, wave, flux, ivar)
         ensembles[tracer].meta = dat[0].header
@@ -755,7 +758,6 @@ def alpha_X2(alpha):
 
 #- Cache files from desimodel to avoid reading them N>>1 times
 _camera_nea_angperpix = None
-_band_ensemble = None
 
 def calc_tsnr_fiberfracs(fibermap, etc_fiberfracs, no_offsets=False):
     '''
@@ -984,7 +986,6 @@ def calc_tsnr2(frame, fiberflat, skymodel, fluxcalib, alpha_only=False, include_
         Assumes DESIMODEL is set and up to date.
     '''
     global _camera_nea_angperpix
-    global _band_ensemble
 
     t0=time.time()
 
@@ -1056,16 +1057,7 @@ def calc_tsnr2(frame, fiberflat, skymodel, fluxcalib, alpha_only=False, include_
         nea, angperpix = read_nea(neafilename)
         _camera_nea_angperpix[camera] = nea, angperpix
 
-    if _band_ensemble is None:
-        _band_ensemble = dict()
-
-    if band in _band_ensemble:
-        ensemble = _band_ensemble[band]
-    else:
-        ensembledir=os.path.join(os.environ["DESIMODEL"],"data/tsnr")
-        log.info("read TSNR ensemble files in {}".format(ensembledir))
-        ensemble = get_ensemble(ensembledir, bands=[band,])
-        _band_ensemble[band] = ensemble
+    ensemble = get_ensemble()
 
     nspec, nwave = fluxcalib.calib.shape