fix: round quantiles when target is integer (#7)

Author: lsorber

README.md

@@ -51,11 +51,11 @@ When the input data is a pandas DataFrame, the output is also a pandas DataFrame
 
 |   house_id |   0.025 |   0.05 |    0.1 |    0.9 |   0.95 |   0.975 |
 |-----------:|--------:|-------:|-------:|-------:|-------:|--------:|
-|       1357 |  114783 | 120894 | 131618 | 175760 | 188051 |  205448 |
-|       2367 |   67416 |  80073 |  86753 | 117854 | 127582 |  142321 |
-|       2822 |  119422 | 132047 | 138724 | 178526 | 197246 |  214205 |
-|       2126 |   94030 |  99849 | 110891 | 150249 | 164703 |  182528 |
-|       1544 |   68996 |  81516 |  88231 | 121774 | 132425 |  147110 |
+|       1357 |  114784 | 120894 | 131618 | 175761 | 188052 |  205449 |
+|       2367 |   67417 |  80074 |  86754 | 117854 | 127583 |  142322 |
+|       2822 |  119423 | 132048 | 138725 | 178526 | 197246 |  214206 |
+|       2126 |   94031 |  99850 | 110891 | 150249 | 164703 |  182528 |
+|       1544 |   68996 |  81516 |  88232 | 121774 | 132425 |  147110 |
 
 Let's visualize the predicted quantiles on the test set:
 
@@ -116,11 +116,11 @@ When the input data is a pandas DataFrame, the output is also a pandas DataFrame
 
 |   house_id |   0.025 |   0.975 |
 |-----------:|--------:|--------:|
-|       1357 |  107202 |  206290 |
-|       2367 |   66665 |  146004 |
-|       2822 |  115591 |  220314 |
-|       2126 |   85288 |  183037 |
-|       1544 |   67889 |  150646 |
+|       1357 |  107203 |  206290 |
+|       2367 |   66665 |  146005 |
+|       2822 |  115592 |  220315 |
+|       2126 |   85288 |  183038 |
+|       1544 |   67890 |  150646 |
 
 ## Contributing
 

src/conformal_tights/_conformal_coherent_quantile_regressor.py

@@ -275,7 +275,10 @@ def predict_quantiles(
         Δŷ_quantiles = Δŷ_quantiles[
             np.arange(Δŷ_quantiles.shape[0]), :, np.argmin(dispersion, axis=-1)
         ]
-        ŷ_quantiles: FloatMatrix[F] = (ŷ[:, np.newaxis] + Δŷ_quantiles).astype(self.y_dtype_)
+        ŷ_quantiles: FloatMatrix[F] = ŷ[:, np.newaxis] + Δŷ_quantiles
+        if self.y_is_integer_:
+            ŷ_quantiles = np.round(ŷ_quantiles)
+        ŷ_quantiles = ŷ_quantiles.astype(self.y_dtype_)
         # Convert ŷ_quantiles to a pandas DataFrame if X is a pandas DataFrame.
         if hasattr(X, "dtypes") and hasattr(X, "index"):
             try: