Change the

main functions in the kaya_factors and kaya_variables modules to compute_
kaya_factors and compute_kaya_variables. Also add test case for GDP (MER)
fallback for Kaya Factors calculation.

Author: zacharyschmidt

pyam/compute.py

@@ -296,7 +296,7 @@ def kaya_variables(self, append=False):
 
         """
 
-        kaya_variables_frame = kaya_variables.kaya_variables(self._df)
+        kaya_variables_frame = kaya_variables.compute_kaya_variables(self._df)
         if kaya_variables_frame is None:
             return None
         if append:
@@ -353,7 +353,7 @@ def kaya_factors(self, append=False):
         kaya_variables = self.kaya_variables(append=False)
         if kaya_variables is None:
             return None
-        kaya_factors_frame = kaya_factors.kaya_factors(kaya_variables)
+        kaya_factors_frame = kaya_factors.compute_kaya_factors(kaya_variables)
         if kaya_factors_frame is None:
             return None
         if append:

pyam/kaya/kaya_factors.py

@@ -2,7 +2,7 @@
 from pyam.kaya import input_variable_names, kaya_factor_names, kaya_variable_names
 
 
-def kaya_factors(kaya_variables_frame):
+def compute_kaya_factors(kaya_variables_frame):
     kaya_factors = pyam.concat(
         [
             _calc_gnp_per_p(kaya_variables_frame),

pyam/kaya/kaya_variables.py

@@ -13,7 +13,7 @@
 ]
 
 
-def kaya_variables(input_data):
+def compute_kaya_variables(input_data):
     if _is_input_data_incomplete(input_data):
         return None
 

tests/test_feature_kaya_factors.py

@@ -113,3 +113,35 @@ def test_calling_kaya_factors_multiple_times():
     obs.compute.kaya_factors(append=True)
     obs.compute.kaya_factors(append=True)
     assert_iamframe_equal(TEST_DF.append(EXP_DF_FOR_APPEND), obs)
+
+def test_kaya_factors_uses_gdp_mer_fallback():
+    """Test that kaya_factors uses GDP_MER when GDP_PPP is not available"""
+    # Create test data without GDP_PPP
+    df_no_gdp_ppp = TEST_DF.filter(variable="GDP|PPP", keep=False)
+
+    # Create expected result using GDP|MER instead of GDP|PPP for calculations
+    exp_no_gdp_ppp = IamDataFrame(
+        pd.DataFrame(
+            [   # 8 EJ / 5 billion USD = 1.6
+                ["FE/GNP", "EJ / USD / billion", 1.6],
+                # 5 billion USD / 1000 million = 0.005
+                ["GNP/P", "USD * billion / million / a", 0.005],
+                ["NFC/TFC", "", 0.833333],
+                ["PEDEq/FE", "", 1.250000],
+                ["PEFF/PEDEq", "", 0.900000],
+                ["TFC/PEFF", "Mt CO2/EJ", 1.333333],
+                ["Population", "million", 1000],
+                ["Total Fossil Carbon", "Mt CO2/yr", 12.0],
+            ],
+            columns=["variable", "unit", 2010],
+        ),
+        model="model_a",
+        scenario="scen_a",
+        region="World",
+    )
+
+    # Compute kaya factors
+    obs = df_no_gdp_ppp.compute.kaya_factors()
+
+    # Verify results match expected
+    assert_iamframe_equal(exp_no_gdp_ppp, obs)