Deal with edge cases for quantile_mapping_curve()

metno · Oct 30, 2020 · b38aa4b · b38aa4b
1 parent 3e4028f
commit b38aa4b
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diff --git a/src/api/quantile_mapping.cpp b/src/api/quantile_mapping.cpp
@@ -3,7 +3,25 @@
 using namespace gridpp;
 
 vec2 gridpp::quantile_mapping_curve(const vec& ref, const vec& fcst, vec quantiles) {
+    if(ref.size() != fcst.size())
+        throw std::invalid_argument("ref and fcst must be of the same size");
+
+    if(quantiles.size() > 0) {
+        for(int i = 0; i < quantiles.size(); i++) {
+            float curr = quantiles[i];
+            if(!gridpp::is_valid(curr) || curr > 1 || curr < 0)
+                throw std::invalid_argument("Quantiles must be >= 0 and <= 1");
+        }
+    }
     vec2 curve(2);
+    if(ref.size() == 0)
+        return curve;
+    else if(ref.size() == 1) {
+        curve[0] = fcst;
+        curve[1] = ref;
+        return curve;
+    }
+
     vec ref_sort = ref;
     std::sort(ref_sort.begin(), ref_sort.end());
     vec fcst_sort = fcst;

diff --git a/tests/quantile_mapping_test.py b/tests/quantile_mapping_test.py
@@ -26,6 +26,41 @@ def test_negative(self):
         new_fcst = gridpp.apply_curve(fcst, curve, gridpp.OneToOne, gridpp.OneToOne)
         np.testing.assert_array_equal(np.sort(ref), new_fcst)
 
+    def test_quantiles(self):
+        ref = np.arange(11)
+        fcst = ref + 2
+        quantiles = [0.1, 0.9]
+        curve = gridpp.quantile_mapping_curve(ref, fcst, quantiles)
+        np.testing.assert_array_equal([1, 9], curve[1])
+        np.testing.assert_array_equal([3, 11], curve[0])
+
+    def test_single_point(self):
+        ref = [1]
+        fcst = [2]
+        curve = gridpp.quantile_mapping_curve(ref, fcst)
+        np.testing.assert_array_almost_equal(curve, [fcst, ref])
+
+    def test_dimension_mismatch(self):
+        ref = [1, 2]
+        fcst = [1, 2, 3]
+        with self.assertRaises(Exception) as e:
+            curve = gridpp.quantile_mapping_curve(ref, fcst)
+        with self.assertRaises(Exception) as e:
+            curve = gridpp.quantile_mapping_curve(ref, fcst, [0.1, 0.9])
+
+    def test_empty_curve(self):
+        ref = []
+        fcst = []
+        np.testing.assert_array_almost_equal([[],[]], gridpp.quantile_mapping_curve(ref, fcst))
+        np.testing.assert_array_almost_equal([[],[]], gridpp.quantile_mapping_curve(ref, fcst, [0.1, 0.9]))
+
+    def test_invalid_argument(self):
+        ref = np.arange(11)
+        fcst = ref + 2
+        quantiles = [0.1, -1]
+        with self.assertRaises(Exception) as e:
+            curve = gridpp.quantile_mapping_curve(ref, fcst, quantiles)
+
 
 if __name__ == '__main__':
     unittest.main()