diff --git a/src/fourier/details/euclidian_maps.hpp b/src/fourier/details/euclidian_maps.hpp
index 67b141b..cfadc72 100644
--- a/src/fourier/details/euclidian_maps.hpp
+++ b/src/fourier/details/euclidian_maps.hpp
@@ -136,14 +136,21 @@ namespace CosmoTool
     {
       const DimArray& dims = this->getDims();
       DimArray d(delta_k.size());
-      for (int q = 0; q < d.size(); q++)
-       {
-         d[q] = p%dims[q];
-         p = (p-d[q])/dims[q];
-       }
+      get_IKvec(p, d);
       get_Kvec(d, kvec);
     }
 
+    void get_IKvec(long p, DimArray& ikvec)
+    {
+      const DimArray& dims = this->getDims();
+      assert(dims.size()==ikvec.size());
+      for (int q = 0; q < ikvec.size(); q++)
+       {
+         ikvec[q] = p%dims[q];
+         p = (p-ikvec[q])/dims[q];
+       }
+    }
+
 
     template<typename Array>
     double get_K(const Array& ik)
diff --git a/src/fourier/details/euclidian_spectrum_1d.hpp b/src/fourier/details/euclidian_spectrum_1d.hpp
index b12864b..291470d 100644
--- a/src/fourier/details/euclidian_spectrum_1d.hpp
+++ b/src/fourier/details/euclidian_spectrum_1d.hpp
@@ -1,6 +1,8 @@
 #ifndef __DETAILS_EUCLIDIAN_SPECTRUM_1D
 #define __DETAILS_EUCLIDIAN_SPECTRUM_1D
 
+#include <boost/function.hpp>
+
 
 namespace CosmoTool
 {