add kwargs option to Cosmology.read_yaml and tests (#829)

* add kwargs option to Cosmology.read_yaml and tests * appease flake8 Co-authored-by: c-d-leonard <[email protected]>
LSSTDESC · Jan 11, 2021 · be756a1 · be756a1
1 parent 641ba87
commit be756a1
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Showing 2 changed files with 16 additions and 1 deletion.
diff --git a/pyccl/core.py b/pyccl/core.py
@@ -221,11 +221,12 @@ def write_yaml(self, filename):
             raise IOError("Unable to write YAML file {}".format(filename))
 
     @classmethod
-    def read_yaml(cls, filename):
+    def read_yaml(cls, filename, **kwargs):
         """Read the parameters from a YAML file.
 
         Args:
             filename (:obj:`str`) Filename to read parameters from.
+            **kwargs (dict) Additional keywords that supersede file contents
         """
         with open(filename, 'r') as fp:
             params = yaml.load(fp, Loader=yaml.Loader)
@@ -256,6 +257,8 @@ def read_yaml(cls, filename):
             inits['m_nu'] = params['m_nu']
             inits['m_nu_type'] = 'list'
 
+        inits.update(kwargs)
+
         return cls(**inits)
 
     def _build_config(

diff --git a/pyccl/tests/test_parameters.py b/pyccl/tests/test_parameters.py
@@ -499,6 +499,18 @@ def test_parameters_read_write():
     assert_almost_equal(params['Neff'], params2['Neff'])
     assert_almost_equal(params['sum_nu_masses'], params2['sum_nu_masses'])
 
+    # check overriding parameters with kwargs
+    params3 = ccl.Cosmology.read_yaml(temp_file_name,
+                                      matter_power_spectrum='emu',
+                                      n_s=1.1)
+    # check unmodified parameters are the same
+    assert_almost_equal(params['Omega_c'], params3['Omega_c'])
+    assert_almost_equal(params['Neff'], params3['Neff'])
+    # check new parameters and config correctly updated
+    assert_almost_equal(1.1, params3['n_s'])
+    assert_almost_equal(params['sum_nu_masses'], params3['sum_nu_masses'])
+    assert params3._config_init_kwargs['matter_power_spectrum'] == 'emu'
+
     # Now make a file that will be deleted so it does not exist
     # and check the right error is raise
     with tempfile.NamedTemporaryFile(delete=True) as tmpfile: