diff --git a/numerical_methods/durand_kerner_roots.c b/numerical_methods/durand_kerner_roots.c
index f29158c4..ef9db916 100644
--- a/numerical_methods/durand_kerner_roots.c
+++ b/numerical_methods/durand_kerner_roots.c
@@ -47,7 +47,7 @@
  * \param[in] x point at which to evaluate the polynomial
  * \returns \f$f(x)\f$
  */
-long double complex poly_function(double *coeffs, unsigned int degree,
+long double complex poly_function(long double *coeffs, unsigned int degree,
                                   long double complex x)
 {
     long double complex out = 0.;
@@ -94,7 +94,7 @@ char check_termination(long double delta)
  */
 int main(int argc, char **argv)
 {
-    double *coeffs = NULL;
+    long double *coeffs = NULL;
     long double complex *s0 = NULL;
     unsigned int degree = 0;
     unsigned int n, i;
@@ -108,8 +108,8 @@ int main(int argc, char **argv)
     }
 
     degree = argc - 1; /* detected polynomial degree */
-    coeffs = (double *)malloc(
-        degree * sizeof(double)); /* store all input coefficients */
+    coeffs = (long double *)malloc(
+        degree * sizeof(long double)); /* store all input coefficients */
     s0 = (long double complex *)malloc(
         (degree - 1) *
         sizeof(long double complex)); /* number of roots = degree-1 */