diff --git a/src/dspline.h b/src/dspline.h
index 3482aa1..1a4b71b 100644
--- a/src/dspline.h
+++ b/src/dspline.h
@@ -8,12 +8,18 @@ using namespace Rcpp;
 // Simple utilities
 
 int fact(int k);
-void CumSum(NumericVector v, int i);
-void RevCumSum(NumericVector v, int i);
-void Diff(NumericVector v, int i);
-void RevDiff(NumericVector v, int i);
-void GapWeight(NumericVector v, int i, NumericVector xd);
-void InvGapWeight(NumericVector v, int i, NumericVector xd);
+template<typename T>
+void CumSum(T& v, int i);
+template<typename T>
+void RevCumSum(T& v, int i);
+template<typename T>
+void Diff(T& v, int i);
+template<typename T>
+void RevDiff(T& v, int i);
+template<typename T, typename U>
+void GapWeight(T& v, int i, U& xd);
+template<typename T, typename U>
+void InvGapWeight(T& v, int i, U& xd);
 
 /******************************************************************************/
 // Divided differences, discrete derivatives, and discrete integrals 
diff --git a/src/utils.cpp b/src/utils.cpp
index efba21d..0fd2eaa 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -2,6 +2,8 @@
 // Simple utilities
 
 #include <Rcpp.h>
+#include <RcppEigen.h>
+#include <Eigen/Sparse>
 using namespace Rcpp;
 
 // Factorial
@@ -12,43 +14,65 @@ int fact(int k) {
 }
 
 // Overwrite v with cumulative sums, starting at i
-void CumSum(NumericVector v, int i) {
+template<typename T>
+void CumSum(T& v, int i) {
   for (int j = i+1; j < v.size(); j++) {
     v[j] += v[j-1];
   }
 }
+template void CumSum<NumericVector>(NumericVector& v, int i);
+template void CumSum<Eigen::VectorXd>(Eigen::VectorXd& v, int i);
 
 // Overwrite v with reverse cumulative sums, ending at i
-void RevCumSum(NumericVector v, int i) {
+template<typename T>
+void RevCumSum(T& v, int i) {
   for (int j = v.size()-2; j >= i; j--) {
     v[j] += v[j+1];
   }
 }
+template void RevCumSum<NumericVector>(NumericVector& v, int i);
+template void RevCumSum<Eigen::VectorXd>(Eigen::VectorXd& v, int i);
 
 // Overwrite v with pairwise differences, starting at i
-void Diff(NumericVector v, int i) {
+template<typename T>
+void Diff(T& v, int i) {
   for (int j = v.size()-1; j >= i; j--) {
     v[j] -= v[j-1];
   }
 }
+template void Diff<NumericVector>(NumericVector& v, int i);
+template void Diff<Eigen::VectorXd>(Eigen::VectorXd& v, int i);
 
 // Overwrite v with reverse pairwise differences, ending at i
-void RevDiff(NumericVector v, int i) {
+template<typename T>
+void RevDiff(T& v, int i) {
   for (int j = i; j < v.size()-1; j++) {
     v[j] -= v[j+1];
   }
 }
+template void RevDiff<NumericVector>(NumericVector& v, int i);
+template void RevDiff<Eigen::VectorXd>(Eigen::VectorXd& v, int i);
 
 // Apply gap weighting to v (wrt xd), starting at i
-void GapWeight(NumericVector v, int i, NumericVector xd) {
+template<typename T, typename U>
+void GapWeight(T& v, int i, U& xd) {
   for (int j = i; j < v.size(); j++) {
     v[j] *= (xd[j] - xd[j-i]) / i;
   }
 }
+template void GapWeight<NumericVector,NumericVector>(NumericVector& v, int i, NumericVector& xd);
+template void GapWeight<NumericVector,Eigen::VectorXd>(NumericVector& v, int i, Eigen::VectorXd& xd);
+template void GapWeight<Eigen::VectorXd,NumericVector>(Eigen::VectorXd& v, int i, NumericVector& xd);
+template void GapWeight<Eigen::VectorXd,Eigen::VectorXd>(Eigen::VectorXd& v, int i, Eigen::VectorXd& xd);
 
 // Apply invesre gap weighting to v (wrt xd), starting at i
-void InvGapWeight(NumericVector v, int i, NumericVector xd) {
+template<typename T, typename U>
+void InvGapWeight(T& v, int i, U& xd) {
   for (int j = i; j < v.size(); j++) {
     v[j] /= (xd[j] - xd[j-i]) / i;
   }
 }
+template void InvGapWeight<NumericVector,NumericVector>(NumericVector& v, int i, NumericVector& xd);
+template void InvGapWeight<NumericVector,Eigen::VectorXd>(NumericVector& v, int i, Eigen::VectorXd& xd);
+template void InvGapWeight<Eigen::VectorXd,NumericVector>(Eigen::VectorXd& v, int i, NumericVector& xd);
+template void InvGapWeight<Eigen::VectorXd,Eigen::VectorXd>(Eigen::VectorXd& v, int i, Eigen::VectorXd& xd);