diff --git a/include/differentiators.h b/include/differentiators.h
index 7768178..6993d98 100644
--- a/include/differentiators.h
+++ b/include/differentiators.h
@@ -191,7 +191,7 @@ template <typename T, int N, typename CNRCoeffs> vectN_t<T, N> GetCNRISDCoeffs()
     vectN_t<T, N> v{};
     const vectN_t<T, N> v0 = CNRCoeffs{}();
     v(M) = 0;
-    for (Eigen::Index k = 1; k < M + 1; ++k) {
+    for (int k = 1; k < M + 1; ++k) {
         v(M - k) = T(2) * k * v0(M - k);
         v(M + k) = T(2) * k * v0(M + k);
     }
diff --git a/tests/noisy_function_generator.h b/tests/noisy_function_generator.h
index 884cfc9..8549327 100644
--- a/tests/noisy_function_generator.h
+++ b/tests/noisy_function_generator.h
@@ -77,11 +77,11 @@ FunctionGenerator<T> polyGenerator(int nrSteps, std::array<T, N> coeffs, T dt)
 
     std::array<T, N - 1> dCoeffs;
     for (size_t i = 1; i < N; ++i)
-        dCoeffs[i - 1] = i * coeffs[i];
+        dCoeffs[i - 1] = static_cast<T>(i) * coeffs[i];
 
     std::array<T, N - 2> ddCoeffs;
     for (size_t i = 1; i < N - 1; ++i)
-        ddCoeffs[i - 1] = i * dCoeffs[i];
+        ddCoeffs[i - 1] = static_cast<T>(i) * dCoeffs[i];
 
     vectX_t<T> f(nrSteps);
     vectX_t<T> df(nrSteps);
@@ -160,11 +160,11 @@ TVFunctionGenerator<T> tvPolyGenerator(int nrSteps, std::array<T, N> coeffs, T m
 
     std::array<T, N - 1> dCoeffs;
     for (size_t i = 1; i < N; ++i)
-        dCoeffs[i - 1] = i * coeffs[i];
+        dCoeffs[i - 1] = static_cast<T>(i) * coeffs[i];
 
     std::array<T, N - 2> ddCoeffs;
     for (size_t i = 1; i < N - 1; ++i)
-        ddCoeffs[i - 1] = i * dCoeffs[i];
+        ddCoeffs[i - 1] = static_cast<T>(i) * dCoeffs[i];
 
     vectX_t<T> t(nrSteps);
     vectX_t<T> f(nrSteps);