diff --git a/external/cosmotool/src/fourier/details/healpix_utility.hpp b/external/cosmotool/src/fourier/details/healpix_utility.hpp
index d989dd8..cf501d6 100644
--- a/external/cosmotool/src/fourier/details/healpix_utility.hpp
+++ b/external/cosmotool/src/fourier/details/healpix_utility.hpp
@@ -52,7 +52,7 @@ namespace CosmoTool
       HealpixSpectrum<T> *new_spectrum = new HealpixSpectrum<T>(in_spec.Lmax());
       T *out_d = new_spectrum->data();
 
-      std::copy(data, data + min(size,new_spectrum->size()), out_d);
+      std::copy(data, data + std::min(size,new_spectrum->size()), out_d);
 
       return Spectrum_ptr(new_spectrum);
     }