add tests to impact function

unit tests for set_step_ImpF
unit tests for set_sigmoid_ImpF

Author: samluethi

climada/entity/impact_funcs/base.py

@@ -159,7 +159,8 @@ def set_sigmoid_ImpF(self, sig_mid, sig_shape, sig_max,
         """ Sigmoid type impact function hinging on three parameter. This type
         of impact function is very flexible for any sort of study/resolution.
         Parameters can be thought of as intercept (sig_mid), slope (sig_shape)
-        and top (sig_max) of a sigmoid.
+        and top (sig_max) of a sigmoid. More precisely, sig_mid refers to the
+        intensity value where MDD equals 50% of sig_max.
 
         For more information: https://en.wikipedia.org/wiki/Logistic_function
 

climada/entity/impact_funcs/test/test_base.py

@@ -35,6 +35,23 @@ def test_calc_mdr_pass(self):
         imp_fun.mdd = np.arange(0, 1, 0.1)
         new_inten = 17.2
         self.assertEqual(imp_fun.calc_mdr(new_inten), 0.029583999999999996)
+        
+    def test_set_step(self):
+        """Check default impact function: step function"""
+        imp_fun = ImpactFunc()
+        imp_fun.set_step_ImpF(5, 0, 10)
+        self.assertTrue(np.array_equal(imp_fun.paa, np.ones(4)))
+        self.assertTrue(np.array_equal(imp_fun.mdd, np.array([0, 0, 1, 1])))
+        self.assertTrue(np.array_equal(imp_fun.intensity, np.array([0, 5, 5, 10])))
+
+    def test_set_sigmoid(self):
+        """Check default impact function: sigmoid function"""
+        imp_fun = ImpactFunc()
+        imp_fun.set_sigmoid_ImpF(50., 2., 1.0, 0, 100)
+        self.assertTrue(np.array_equal(imp_fun.paa, np.ones(20)))
+        self.assertEqual(imp_fun.mdd[10], 0.5)
+        self.assertEqual(imp_fun.mdd[-1], 1.0)
+        self.assertTrue(np.array_equal(imp_fun.intensity, np.arange(0, 100, 5)))
 
 # Execute Tests
 if __name__ == "__main__":