diff --git a/src/velociraptor_interface.c b/src/velociraptor_interface.c
index cf2a9af3c658cc3c06e7f0431b44eeee3bf5eaa4..da54df75e5bc6f7f252aae5b2ae8e15104d78ac4 100644
--- a/src/velociraptor_interface.c
+++ b/src/velociraptor_interface.c
@@ -98,7 +98,7 @@ void velociraptor_init(struct engine *e) {
     }
     else sim_info.period = 0.0;
     sim_info.zoomhigresolutionmass = -1.0; /* Placeholder. */
-    sim_info.interparticlespacing = sim_info.period / pow(total_nr_dmparts, 1./3.);
+    sim_info.interparticlespacing = sim_info.period / cbrt(total_nr_dmparts);
     sim_info.icosmologicalsim = (e->policy & engine_policy_cosmology);
     sim_info.spacedimension[0] = unit_info.lengthtokpc * s->dim[0];
     sim_info.spacedimension[1] = unit_info.lengthtokpc * s->dim[1];