Introducing gammapy.utils.serialization

gammapy/catalog/gammacat.py

@@ -13,7 +13,6 @@
 from ..extern import six
 from astropy import units as u
 from astropy.table import Table
-from ..utils.modeling import SourceModel, SourceLibrary, UnknownModelError
 from ..utils.scripts import make_path
 from ..spectrum import FluxPoints
 from ..spectrum.models import PowerLaw, PowerLaw2, ExponentialCutoffPowerLaw

gammapy/cube/models.py

@@ -5,12 +5,32 @@
 import astropy.units as u
 from astropy.utils import lazyproperty
 from ..utils.modeling import ParameterList
+from ..utils.scripts import make_path
 
 __all__ = [
+    'SourceLibrary',
     'SkyModel',
     'SkyModelMapEvaluator',
 ]
 
+class SourceLibrary(object):
+    """Collection of `~gammapy.cube.models.SkyModel`
+
+    Parameters
+    ----------
+    skymodels : list of `~gammapy.cube.models.SkyModel`
+        Sky models
+    """
+    def __init__(self, skymodels):
+        self.skymodels = skymodels
+
+    @classmethod
+    def from_xml(cls, filename):
+        from ..utils.serialization import xml_to_source_library
+        path = make_path(filename)
+        xml = path.read_text()
+        return xml_to_source_library(xml)
+
 
 class SkyModel(object):
     """Sky model component.
@@ -27,11 +47,14 @@ class SkyModel(object):
         Spatial model (must be normalised to integrate to 1)
     spectral_model : `~gammapy.spectrum.models.SpectralModel`
         Spectral model
+    name : str
+        Model identifier
     """
 
-    def __init__(self, spatial_model, spectral_model):
+    def __init__(self, spatial_model, spectral_model, name='SkyModel'):
         self._spatial_model = spatial_model
         self._spectral_model = spectral_model
+        self.name = name
         self._init_parameters()
 
     def _init_parameters(self):

gammapy/spectrum/models.py

@@ -1180,10 +1180,12 @@ def __init__(self, energy, values, scale=1, scale_logy=True):
 
     @classmethod
     def read_xspec_model(cls, filename, param):
-        """A Table containing absorbed values from a XSPEC model
-        as a function of energy.
-        Todo:
-        Format of the file should be described and discussed in
+        """Read XSPEC table model
+
+        The input is a table containing absorbed values from a XSPEC model as a
+        function of energy.
+
+        TODO: Format of the file should be described and discussed in
         https://gamma-astro-data-formats.readthedocs.io/en/latest/index.html
 
         Parameters
@@ -1230,6 +1232,26 @@ def read_xspec_model(cls, filename, param):
 
         return cls(energy=energy, values=values, scale_logy=False)
 
+    @classmethod
+    def read_fermi_isotropic_model(cls, filename):
+        """Read Fermi isotropic diffuse model
+
+        see `LAT Background models <https://fermi.gsfc.nasa.gov/ssc/data/access/lat/BackgroundModels.html>`_
+
+        Parameters
+        ----------
+        filename : `str`
+            filename
+        param : float
+            Model parameter value
+        """
+        filename = str(make_path(filename))
+        vals = np.loadtxt(filename)
+        energy = vals[:,0] * u.MeV
+        values = vals[:,1] * u.Unit('MeV-1 s-1 cm-2')
+
+        return cls(energy=energy, values=values, scale_logy=False)
+
     def evaluate(self, energy, scale):
         """Evaluate the model (static function)."""
         # What's with all this checking?