diff --git a/python/cosmotool/fftw.py b/python/cosmotool/fftw.py
index da0c094..0ba51bf 100644
--- a/python/cosmotool/fftw.py
+++ b/python/cosmotool/fftw.py
@@ -10,7 +10,7 @@ class CubeFT(object):
       self.align = pyfftw.simd_alignment
       self.L = float(L)
       self.max_cpu = multiprocessing.cpu_count() if max_cpu < 0 else max_cpu
-      self._dhat = pyfftw.n_byte_align_empty((self.N,self.N,self.N/2+1), self.align, dtype='complex64')
+      self._dhat = pyfftw.n_byte_align_empty((self.N,self.N,self.N//2+1), self.align, dtype='complex64')
       self._density = pyfftw.n_byte_align_empty((self.N,self.N,self.N), self.align, dtype='float32')
       self._irfft = pyfftw.FFTW(self._dhat, self._density, axes=(0,1,2), direction='FFTW_BACKWARD', threads=self.max_cpu)#, normalize_idft=False)
       self._rfft = pyfftw.FFTW(self._density, self._dhat, axes=(0,1,2), threads=self.max_cpu) #, normalize_idft=False)