Merge pull request #857 from LSSTDESC/camb_DEmodel

Camb dark energy model

pyccl/boltzmann.py

@@ -139,9 +139,20 @@ def get_camb_pk_lin(cosmo, nonlin=False):
         cp.ombh2 * (camb.constants.COBE_CMBTemp / cp.TCMB) ** 3,
         delta_neff)
 
+    camb_de_models = ['DarkEnergyPPF', 'ppf', 'DarkEnergyFluid', 'fluid']
+    camb_de_model = extra_camb_params.get('dark_energy_model', 'fluid')
+    if camb_de_model not in camb_de_models:
+        raise ValueError("The only dark energy models CCL supports with"
+                         " camb are fluid and ppf.")
     cp.set_classes(
-        dark_energy_model=camb.dark_energy.DarkEnergyFluid
+        dark_energy_model=camb_de_model
     )
+
+    if camb_de_model not in camb_de_models[:2] and cosmo['wa'] and \
+            (cosmo['w0'] < -1 - 1e-6 or
+                1 + cosmo['w0'] + cosmo['wa'] < - 1e-6):
+        raise ValueError("If you want to use w crossing -1,"
+                         " then please set the dark_energy_model to ppf.")
     cp.DarkEnergy.set_params(
         w=cosmo['w0'],
         wa=cosmo['wa']
@@ -256,6 +267,13 @@ def get_isitgr_pk_lin(cosmo):
             *e.args)
         raise
 
+    # Get extra CAMB parameters that were specified
+    extra_camb_params = {}
+    try:
+        extra_camb_params = cosmo["extra_parameters"]["camb"]
+    except (KeyError, TypeError):
+        pass
+
     # z sampling from CCL parameters
     na = lib.get_pk_spline_na(cosmo.cosmo)
     status = 0
@@ -318,7 +336,7 @@ def get_isitgr_pk_lin(cosmo):
 
     delta_neff = cosmo['Neff'] - 3.046  # used for BBN YHe comps
 
-    # ISiTGR built on  CAMB which defines a neutrino degeneracy
+    # ISiTGR built on CAMB which defines a neutrino degeneracy
     # factor as T_i = g^(1/4)*T_nu
     # where T_nu is the standard neutrino temperature from first order
     # computations
@@ -351,9 +369,19 @@ def get_isitgr_pk_lin(cosmo):
         cp.ombh2 * (isitgr.constants.COBE_CMBTemp / cp.TCMB) ** 3,
         delta_neff)
 
+    camb_de_models = ['DarkEnergyPPF', 'ppf', 'DarkEnergyFluid', 'fluid']
+    camb_de_model = extra_camb_params.get('dark_energy_model', 'fluid')
+    if camb_de_model not in camb_de_models:
+        raise ValueError("The only dark energy models CCL supports with"
+                         " camb are fluid and ppf.")
     cp.set_classes(
-        dark_energy_model=isitgr.dark_energy.DarkEnergyFluid
+        dark_energy_model=camb_de_model
     )
+    if camb_de_model not in camb_de_models[:2] and cosmo['wa'] and \
+            (cosmo['w0'] < -1 - 1e-6 or
+                1 + cosmo['w0'] + cosmo['wa'] < - 1e-6):
+        raise ValueError("If you want to use w crossing -1,"
+                         " then please set the dark_energy_model to ppf.")
     cp.DarkEnergy.set_params(
         w=cosmo['w0'],
         wa=cosmo['wa']

pyccl/core.py

@@ -185,6 +185,7 @@ class Cosmology(object):
         * `HMCode_logT_AGN`
         * `kmax`
         * `lmax`
+        * `dark_energy_model`
 
     Consult the CAMB documentation for their usage. These parameters are passed
     in a :obj:`dict` to `extra_parameters` as::

pyccl/tests/test_power.py

@@ -588,3 +588,25 @@ def test_input_nonlin_raises():
         nonlinear_model='halofit')
     assert 'a:b' in cosmo_input._pk_nl
     assert cosmo_input.has_nonlin_power
+
+
+def test_camb_de_model():
+    """Check that the dark energy model for CAMB has been properly defined."""
+    with pytest.raises(ValueError):
+        cosmo = ccl.CosmologyVanillaLCDM(
+            transfer_function='boltzmann_camb',
+            extra_parameters={"camb": {"dark_energy_model": "pf"}})
+        ccl.linear_matter_power(cosmo, 1, 1)
+
+    """Check that w is not less than -1, if the chosen dark energy model for
+    CAMB is fluid."""
+    with pytest.raises(ValueError):
+        cosmo = ccl.CosmologyVanillaLCDM(
+            transfer_function='boltzmann_camb', w0=-1, wa=-1)
+        ccl.linear_matter_power(cosmo, 1, 1)
+
+    """Check that ppf is running smoothly."""
+    cosmo = ccl.CosmologyVanillaLCDM(
+        transfer_function='boltzmann_camb', w0=-1, wa=-1,
+        extra_parameters={"camb": {"dark_energy_model": "ppf"}})
+    assert np.isfinite(ccl.linear_matter_power(cosmo, 1, 1))