diff --git a/src/EXTRA-PAIR/pair_coul_ctip.cpp b/src/EXTRA-PAIR/pair_coul_ctip.cpp
index be07d07e35..b0d1db455d 100644
--- a/src/EXTRA-PAIR/pair_coul_ctip.cpp
+++ b/src/EXTRA-PAIR/pair_coul_ctip.cpp
@@ -309,7 +309,7 @@ void PairCoulCTIP::init_style()
     for (int elt2 = 0; elt2 < nelements; elt2++) {
       shield[elt1][elt2] = sqrt(params[elt1].gamma * params[elt2].gamma);
       shieldcu[elt1][elt2] = shield[elt1][elt2] * shield[elt1][elt2] * shield[elt1][elt2];
-      reffc[elt1][elt2] = std::cbrt(cut_coulcu + 1.0 / shieldcu[elt1][elt2]);
+      reffc[elt1][elt2] = cbrt(cut_coulcu + 1.0 / shieldcu[elt1][elt2]);
       reffcsq[elt1][elt2] = reffc[elt1][elt2] * reffc[elt1][elt2];
       reffc4[elt1][elt2] = reffcsq[elt1][elt2] * reffcsq[elt1][elt2];
       reffc7[elt1][elt2] = reffc4[elt1][elt2] * reffcsq[elt1][elt2] * reffc[elt1][elt2];
diff --git a/src/QEQ/fix_qeq_ctip.cpp b/src/QEQ/fix_qeq_ctip.cpp
index b86549d2a7..0532f11c44 100644
--- a/src/QEQ/fix_qeq_ctip.cpp
+++ b/src/QEQ/fix_qeq_ctip.cpp
@@ -122,7 +122,7 @@ void FixQEqCTIP::init()
       (t_cut * (A1 + t_cut * (A2 + t_cut * (A3 + t_cut * (A4 + t_cut * A5)))) * erfcd_cut) / r;
 
   for (int elt1 = 0; elt1 < ntypes; elt1++) {
-    reff[elt1] = std::cbrt(rsq * r + 1.0 / (gamma[elt1 + 1] * gamma[elt1 + 1] * gamma[elt1 + 1]));
+    reff[elt1] = cbrt(rsq * r + 1.0 / (gamma[elt1 + 1] * gamma[elt1 + 1] * gamma[elt1 + 1]));
     reffsq[elt1] = reff[elt1] * reff[elt1];
     reff4[elt1] = reffsq[elt1] * reffsq[elt1];
     reff7[elt1] = reff4[elt1] * reffsq[elt1] * reff[elt1];