how to recover the other half of complex modes along the z axis

[rahima-mokeddem]

Hello,

I am trying to calculate the displacement field in Fourier space, so I am using r2c() to transform the density field from real to complex space but i see in the documentation that : "This type of FFT uses the symmetry of real-valued quantities to store only half of the complex modes along the z axis."

Now i am wondering if there's a way to recover the missing half of the complex mode along the z axis?