From 1b53f09c3a9dcd64dd281c1955b062fc28999366 Mon Sep 17 00:00:00 2001
From: Gilles <erans@apache.org>
Date: Thu, 15 Jun 2017 14:21:21 +0200
Subject: [PATCH] MATH-1419

---
 src/changes/changes.xml                                        | 3 +++
 .../math4/analysis/polynomials/PolynomialSplineFunction.java   | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 90df1e132..9e4f57965 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -54,6 +54,9 @@ If the output is not quite correct, check for invisible trailing spaces!
     </release>
 
     <release version="4.0" date="XXXX-XX-XX" description="">
+      <action dev="erans" type="fix" issue="MATH-1419" due-to="Hang Park">
+        "PolynomialSplineFunction": incorrect usage of exception.
+      </action>
       <action dev="kinow" type="fix" issue="MATH-1413">
         add generics to the Frequency class
       </action>
diff --git a/src/main/java/org/apache/commons/math4/analysis/polynomials/PolynomialSplineFunction.java b/src/main/java/org/apache/commons/math4/analysis/polynomials/PolynomialSplineFunction.java
index b842a407f..d7263c2fd 100644
--- a/src/main/java/org/apache/commons/math4/analysis/polynomials/PolynomialSplineFunction.java
+++ b/src/main/java/org/apache/commons/math4/analysis/polynomials/PolynomialSplineFunction.java
@@ -105,7 +105,7 @@ public class PolynomialSplineFunction implements UnivariateDifferentiableFunctio
         }
         if (knots.length < 2) {
             throw new NumberIsTooSmallException(LocalizedFormats.NOT_ENOUGH_POINTS_IN_SPLINE_PARTITION,
-                                                2, knots.length, false);
+                                                knots.length, 2, true);
         }
         if (knots.length - 1 != polynomials.length) {
             throw new DimensionMismatchException(polynomials.length, knots.length);