diff --git a/unsupported/Eigen/src/NonLinear/MathFunctions.h b/unsupported/Eigen/src/NonLinear/MathFunctions.h
index cb0ded33c..d4efa5e01 100644
--- a/unsupported/Eigen/src/NonLinear/MathFunctions.h
+++ b/unsupported/Eigen/src/NonLinear/MathFunctions.h
@@ -250,17 +250,16 @@ template<typename Functor, typename Scalar>
 int ei_lmdif1(
         Matrix< Scalar, Dynamic, 1 >  &x,
         Matrix< Scalar, Dynamic, 1 >  &fvec,
-        VectorXi &iwa,
         Scalar tol = ei_sqrt(epsilon<Scalar>())
         )
 {
     int n = x.size();
     int ldfjac = fvec.size();
     int lwa = ldfjac*n+5*n+ldfjac;
+    VectorXi iwa(n);
     Matrix< Scalar, Dynamic, 1 > wa(lwa);
     Matrix< Scalar, Dynamic, Dynamic > fjac(ldfjac, n);
 
-    iwa.resize(n);
     wa.resize(lwa);
     return lmdif1_template<Scalar> (
             Functor::f, 0,
diff --git a/unsupported/test/NonLinear.cpp b/unsupported/test/NonLinear.cpp
index ff94198c2..7591634ff 100644
--- a/unsupported/test/NonLinear.cpp
+++ b/unsupported/test/NonLinear.cpp
@@ -681,13 +681,12 @@ void testLmdif1()
   int m=15, n=3, info;
 
   VectorXd x(n), fvec(m);
-  VectorXi iwa;
 
   /* the following starting values provide a rough fit. */
   x.setConstant(n, 1.);
 
   // do the computation
-  info = ei_lmdif1<lmdif1_functor,double>(x, fvec, iwa);
+  info = ei_lmdif1<lmdif1_functor,double>(x, fvec);
 
   // check return value
   VERIFY( 1 == info);