diff --git a/src/main/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolator.java b/src/main/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolator.java
index ad1e7b2f3..1c7603550 100644
--- a/src/main/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolator.java
+++ b/src/main/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolator.java
@@ -36,7 +36,7 @@ import org.apache.commons.math3.optim.SimpleVectorValueChecker;
  * @since 2.2
  */
 public class SmoothingPolynomialBicubicSplineInterpolator
-    extends PiecewiseBicubicSplineInterpolator {
+    extends BicubicSplineInterpolator {
     /** Fitter for x. */
     private final PolynomialFitter xFitter;
     /** Degree of the fitting polynomial. */
@@ -92,7 +92,7 @@ public class SmoothingPolynomialBicubicSplineInterpolator
      * {@inheritDoc}
      */
     @Override
-    public PiecewiseBicubicSplineInterpolatingFunction interpolate(final double[] xval,
+    public BicubicSplineInterpolatingFunction interpolate(final double[] xval,
                                                           final double[] yval,
                                                           final double[][] fval)
         throws NoDataException, NullArgumentException,