Merge pull request #825 from mperrin/improve_speed_siaf

Performance enhancement: avoid repeated slow loads of the SIAF

webbpsf/distortion.py

@@ -7,6 +7,7 @@
 from scipy.ndimage import rotate
 
 from soc_roman_tools.siaf.siaf import RomanSiaf
+import webbpsf.webbpsf_core
 
 def _get_default_siaf(instrument, aper_name):
     """
@@ -39,7 +40,7 @@ def _get_default_siaf(instrument, aper_name):
         siaf = RomanSiaf()
         aper = siaf[aper_name]
     else:
-        siaf = pysiaf.Siaf(siaf_name)
+        siaf = webbpsf.webbpsf_core.get_siaf_with_caching(siaf_name)
         aper = siaf.apertures[aper_name]
 
     return aper

webbpsf/opds.py

@@ -1226,7 +1226,7 @@ def __init__(self, name='Unnamed OPD', opd=None, opd_index=0, transmission=None,
         elif 'nrs' in control_point_detector:
                 control_point_instr = 'nirspec'
 
-        self.ote_control_point = pysiaf.Siaf(control_point_instr)[self.control_point_fieldpoint.upper()].reference_point('tel')*u.arcsec
+        self.ote_control_point = webbpsf.webbpsf_core.get_siaf_with_caching(control_point_instr)[self.control_point_fieldpoint.upper()].reference_point('tel')*u.arcsec
 
         if zero:
             self.zero()

webbpsf/optics.py

@@ -12,6 +12,7 @@
 from scipy.interpolate import griddata, RegularGridInterpolator
 from scipy.ndimage import rotate
 
+from . import webbpsf_core
 from . import utils
 from . import constants
 
@@ -735,7 +736,7 @@ def __init__(self, name="unnamed BLC", kind='nircamcircular', module='A', nd_squ
             raise NotImplementedError("invalid name for NIRCam occulter: " + self.name)
 
         # EDIT: updated on 8 Dec 2021 to grab offsets directly from pySIAF
-        self.siaf = pysiaf.Siaf('NIRCAM')
+        self.siaf = webbpsf_core.get_siaf_with_caching('NIRCAM')
         self.offset_swb = {filt: self.get_bar_offset_from_siaf(filt, channel='SW')
                            for filt in ["F182M", "F187N", "F210M", "F212N", "F200W", 'narrow']}
         self.offset_lwb = {filt: self.get_bar_offset_from_siaf(filt, channel='LW')

webbpsf/webbpsf_core.py

@@ -22,6 +22,7 @@
 import os
 import glob
 from collections import namedtuple, OrderedDict
+import functools
 import numpy as np
 import scipy.interpolate, scipy.ndimage
 
@@ -753,7 +754,7 @@ class JWInstrument(SpaceTelescopeInstrument):
     def __init__(self, *args, **kwargs):
         super(JWInstrument, self).__init__(*args, **kwargs)
 
-        self.siaf = pysiaf.Siaf(self.name)
+        self.siaf = get_siaf_with_caching(self.name)
 
         opd_path = os.path.join(self._datapath, 'OPD')
         self.opd_list = []
@@ -2932,6 +2933,13 @@ def calc_or_load_PSF(filename, inst, overwrite=False, **kwargs):
 
 #########################
 
+@functools.lru_cache
+def get_siaf_with_caching(instrname):
+    """ Parsing and loading the SIAF information is particularly time consuming,
+    (can be >0.1 s per call, so multiple invokations can be a large overhead)
+    Therefore avoid unnecessarily reloading it by caching results.
+    This is a small speed optimization. """
+    return pysiaf.Siaf(instrname)
 
 class DetectorGeometry(object):
     """ Utility class for converting between detector coordinates