math_65.diff

diff --git a/src/main/java/org/apache/commons/math/optimization/general/AbstractLeastSquaresOptimizer.java b/src/main/java/org/apache/commons/math/optimization/general/AbstractLeastSquaresOptimizer.java
index 30ebfff21..37bca9119 100644
--- a/src/main/java/org/apache/commons/math/optimization/general/AbstractLeastSquaresOptimizer.java
+++ b/src/main/java/org/apache/commons/math/optimization/general/AbstractLeastSquaresOptimizer.java
@@ -252,6 +252,19 @@ public abstract class AbstractLeastSquaresOptimizer implements DifferentiableMul
      * @return chi-square value
      */
     public double getChiSquare() {
+        if (Boolean.parseBoolean(System.getProperty("defects4j.instrumentation.enabled"))) { // defects4j.instrumentation
+            double returnValue = getChiSquare_original(); // defects4j.instrumentation
+            if (getRMS() != Math.sqrt(returnValue / rows)) { // defects4j.instrumentation
+                throw new RuntimeException("[Defects4J_BugReport_Violation]"); // defects4j.instrumentation
+            } else { // defects4j.instrumentation
+                return returnValue; // defects4j.instrumentation
+            } // defects4j.instrumentation
+        } else { // defects4j.instrumentation
+            return getChiSquare_original(); // defects4j.instrumentation
+        } // defects4j.instrumentation
+    } // defects4j.instrumentation
+
+    public double getChiSquare_original() { // defects4j.instrumentation
         double chiSquare = 0;
         for (int i = 0; i < rows; ++i) {
             final double residual = residuals[i];