add utility to write raw files from eimages

desc_roman_sims/__init__.py

@@ -1 +1,2 @@
 from .galsim_job_generator import *
+from .raw_file_writer import *

desc_roman_sims/raw_file_writer.py

@@ -0,0 +1,46 @@
+import os
+import logging
+import galsim
+import imsim
+
+all = ["RawFileWriter"]
+
+
+class RawFileWriter:
+    """Class to write raw files from eimage files"""
+    def __init__(self, readout_time=3., dark_current=0.02, camera=None,
+                 pcti=1e-6, scti=1e-6, bias_level=1000., bias_levels_file=None,
+                 logger=None, rng=None):
+        self.readout_params = dict(readout_time=readout_time,
+                                   dark_current=dark_current,
+                                   camera=camera, pcti=pcti, scti=scti,
+                                   bias_level=bias_level,
+                                   bias_levels_file=bias_levels_file)
+        if logger is None:
+            self.logger = logging.getLogger()
+        else:
+            self.logger = logger
+        if rng is None:
+            self.rng = galsim.BaseDeviate()
+        else:
+            self.rng = rng
+
+    @staticmethod
+    def _read_eimage(eimage_file):
+        eimage = galsim.fits.read(eimage_file)
+        hdus = galsim.fits.readFile(eimage_file)
+        eimage.header = hdus[0].header
+        wcs, _ = galsim.fits.readFromFitsHeader(eimage.header)
+        eimage.wcs = wcs
+        return eimage
+
+    def write(self, eimage_file, outfile=None):
+        if outfile is None:
+            outfile = (os.path.basename(eimage_file).replace("eimage", "amp")
+                       + ".fz")
+        eimage = self._read_eimage(eimage_file)
+
+        ccd_readout = imsim.CcdReadout(eimage, self.logger,
+                                       **self.readout_params)
+        hdus = ccd_readout.prepare_hdus(self.rng)
+        ccd_readout.write_raw_file(hdus, outfile)