diff --git a/unsupported/Eigen/src/NonLinear/fdjac1.h b/unsupported/Eigen/src/NonLinear/fdjac1.h
index 7c317df28..64c742ab7 100644
--- a/unsupported/Eigen/src/NonLinear/fdjac1.h
+++ b/unsupported/Eigen/src/NonLinear/fdjac1.h
@@ -6,9 +6,7 @@ int ei_fdjac1(
         Matrix< Scalar, Dynamic, 1 >  &fvec,
         Matrix< Scalar, Dynamic, Dynamic > &fjac,
         int ml, int mu,
-        Scalar epsfcn,
-        Matrix< Scalar, Dynamic, 1 >  &wa1,
-        Matrix< Scalar, Dynamic, 1 >  &wa2)
+        Scalar epsfcn)
 {
     /* Local variables */
     Scalar h;
@@ -20,6 +18,9 @@ int ei_fdjac1(
     /* Function Body */
     const Scalar epsmch = epsilon<Scalar>();
     const int n = x.size();
+    assert(fvec.size()==n);
+    Matrix< Scalar, Dynamic, 1 >  wa1(n);
+    Matrix< Scalar, Dynamic, 1 >  wa2(n);
 
     eps = ei_sqrt((std::max(epsfcn,epsmch)));
     msum = ml + mu + 1;
diff --git a/unsupported/Eigen/src/NonLinear/fdjac2.h b/unsupported/Eigen/src/NonLinear/fdjac2.h
index bc3a82106..8766a9566 100644
--- a/unsupported/Eigen/src/NonLinear/fdjac2.h
+++ b/unsupported/Eigen/src/NonLinear/fdjac2.h
@@ -5,8 +5,7 @@ int ei_fdjac2(
         Matrix< Scalar, Dynamic, 1 >  &x,
         Matrix< Scalar, Dynamic, 1 >  &fvec,
         Matrix< Scalar, Dynamic, Dynamic > &fjac,
-        Scalar epsfcn,
-        Matrix< Scalar, Dynamic, 1 >  &wa)
+        Scalar epsfcn)
 {
     /* Local variables */
     Scalar h, temp;
@@ -16,6 +15,7 @@ int ei_fdjac2(
     const Scalar epsmch = epsilon<Scalar>();
     const int n = x.size();
     const Scalar eps = ei_sqrt((std::max(epsfcn,epsmch)));
+    Matrix< Scalar, Dynamic, 1 >  wa(fvec.size());
 
     for (int j = 0; j < n; ++j) {
         temp = x[j];
diff --git a/unsupported/Eigen/src/NonLinear/hybrd.h b/unsupported/Eigen/src/NonLinear/hybrd.h
index ef310b5e1..dcabc8f72 100644
--- a/unsupported/Eigen/src/NonLinear/hybrd.h
+++ b/unsupported/Eigen/src/NonLinear/hybrd.h
@@ -93,7 +93,7 @@ int ei_hybrd(
         /* calculate the jacobian matrix. */
 
         iflag = ei_fdjac1(Functor, x, fvec, fjac,
-                nb_of_subdiagonals, nb_of_superdiagonals, epsfcn, wa1, wa2);
+                nb_of_subdiagonals, nb_of_superdiagonals, epsfcn);
         nfev += msum;
         if (iflag < 0)
             break;
diff --git a/unsupported/Eigen/src/NonLinear/lmdif.h b/unsupported/Eigen/src/NonLinear/lmdif.h
index 3bf99e658..1a1c32e84 100644
--- a/unsupported/Eigen/src/NonLinear/lmdif.h
+++ b/unsupported/Eigen/src/NonLinear/lmdif.h
@@ -72,7 +72,7 @@ int ei_lmdif(
 
         /* calculate the jacobian matrix. */
 
-        iflag = ei_fdjac2(Functor, x, fvec, fjac, epsfcn, wa4);
+        iflag = ei_fdjac2(Functor, x, fvec, fjac, epsfcn);
         nfev += n;
         if (iflag < 0)
             break;